Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02207543 1997-OS-28
CAM-OPERATED TIMER PAWL DRIVE
BACKGROUND
This application is related to the following co-pending applications filed on
the same day as this application entitled: Cam-Operated Timer, Cam-Operated
Timer Motor, Timer Camstack and Clutch, Cam-Operated Timer Blade Switches,
Cam-Operated Timer Quiet Cycle Selector, Cam-Operated Timer Subinterval
Switch, and Cam-Operated Timer Test B'rocedure.
This invention relates to cam-operated timers, and more specifically to cam-
operated timer with a pawl drive system that incrementally rotates a camstack.
Cam-operated timers have been used for years to control the functioning of
appliances such as clothes washing machines, clothes dryers, and dishwashers.
Cam-operated timers used in appliances operate to control various appliance
functions in accordance with a predetermined program. Examples of appliance
functions that can be controlled by a cam-operated timer are: agitation,
washing,
spinning, drying, detergent dispensing, hot water filling, cold water filling,
and
water draining.
Cam-operated timers typically have a housing with a control shaft that
serves as an axis of rotation for a drum-shaped cam which may be referred to
as
a camstack. The camstack is connected to a drive system that is powered by an
electric motor to rotate the camstack. Camstack program profiles or blades
carry
the control information to operate blade switches. When the camstack rotates,
the
cam blades are engaged by switches that open and close in response to the cam
blade program. A knob is generally placed on the end of the control shaft
which
extends through the appliance control console for an appliance operator to
select
an appliance program.
Some previous cam-operated timer pawl drive systems employ an eccentric
drive cam to operate a drive pawl. The eccentric typically engages a surface
on
the drive pawl for 360°. An eccentric drive will typically operate the
drive pawl
throughout its stroke or a portion of the stroke typically greater than
60° of drive
cam rotation. Eccentric type drives provide velocity and torque curves that
are
inverse to each other thus imposing some restrictions upon when appliance
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functions can occur during an increment of advance. Also since a cam-operated
timer sub-interval switch is controlled by the drive cam, the requirement for
about
60° to 180° of drive cam rotation to be used for drive pawl
advance imposes some
restrictions on when the subinterval switch can be used. An eccentric type
drive is
disclosed in U.S. Patent No. 3,738,185 issued to Wooley. An example of an
3eeccentric type drive that disengages from the drive pawl is disclosed in
U.S.
Patent No. 4,319,101 issued to Bolin.
To ensure the drive pawl moves in a near linear path, some eccentric drive
have a pin on the drive pawl that engages a track to guide the drive pawl in a
linearly path. Another system some eccentric drives used to guide the drive
pawl
along a near linear path is a biasing cam to position the drive pawl. A pawl
drive
system using a biasing cam is disclosed in U.S. Patent No. 4,536,626 issued to
Wojtanek.
Cam-operated timers are complex electro-mechanical devices having many
mechanical components inter-operating with each other under close tolerances.
One of the primary reasons that previous cam-operated timers have not been
assembled with a great deal of automation equipment is that the timer design
requires components to be assembled from a variety of axes. Manual assembly of
a complex device such as a cam-operated timer compared to automated assembly
can require more time and generate more quality defects. Automated assembly of
a cam-operated timer is desirable because automated assembly should be quicker
and have less quality defects than can be achieved economically with manual
assembly.
Some previous cam-operated timers have employed a metal housing to
contain timer components. The metal housing is typically formed from two or
more pieces of sheet metal that are fastened together to form a partially
enclosed
housing. A metal housing is typically required to be electrically insulated
from the
appliance and also typically requires connection of a grounding strap.
Additionally
a metal housing does not dampen the clicking sounds that can be generated by a
cam-operated timer's drive or cam followers. The partially enclosed housing
can
permit contaminates such as dust or lint to enter the cam operated timer and
interfere with electrical contacts or other mechanical components. Since the
metal
housing is typically formed from two or more pieces of metal, maintenance of
close component tolerances in relation to each other can be difficult. An
example
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of a metal enclosure is disclosed in U.S. Patent No. 4,228,690 issued to Ring.
Some previous cam-operated timers designed for relatively simple
applications, such as a refrigerator freezer defrost timer, have employed a
plastic
housing to contain timer components. An example of a plastic enclosure for a
cam-
operated timer that does employ a small camstack is disclosed in U.S. Patent
No.
4,636,595 issued to Smock et al. An example of a plastic enclosure for a cam-
operated timer that does not employ a camstack, but a pancake cam, is
disclosed in
U.S. Patent No. 4,760,219 issued to Daniell et al.
Cam-operated timers are typically installed with fasteners in appliance
consoles where space can be very limited. A ground strap is usually run from
the
cam-operated metal housing to the appliance console. When a cam-operated timer
requires separate fasteners and a ground strap it is difficult for an
appliance
manufacturer to automate installation of the cam-operated timer into their
appliance.
Previous cam-operated timers have been tested for proper operation by
connecting the timer switches to an electrical analysis device, directing
current
through the timer's motor, and allowing the gear train to drive the camstack
which
then operates the switches of the timer. If the electrical characteristics of
the timer
match predetermined criteria, then the timer passes the test and is ready for
sale.
The amount of time that is required for a typical timer to complete a
revolution of its
camstack when driven by its motor and gear train is often in excess of one
hour.
This means that the testing time for previous cam-operated timers is also in
excess
of one hour.
SUMMARY
The invention provides a cam-operated timer that has a housing designed to
accept components assembled from a limited number of straight axes to simplify
assembly and permit greater automation of assembly. The invention also
provides a
cam-operated timer with components to be installed and positioned in relation
to
each other in a housing with integral molded mounting details, so there is
less
tolerance variation in the installation of timer components. Further, the
invention
provides a cam-operated timer housing that is formed from a material that
electrically insulates electrical components and encloses timer components to
provide protection from contaminates, and eliminates the need for a ground
strap.
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The invention also provides a cam-operated timer which permits an appliance
manufacturer to install the cam-operated timer in an appliance without
separate
fasteners such as screws or nuts and bolts and without a ground strap. The
invention also provides a cam-operated timer having mounting fasteners
integral to
the timer housing, so the cam-operated timer can be installed in an appliance
console without the need for separate mounting hardware, and installation of
the
cam-operated timer in the appliance control console can be automated. The
invention allows the camstack to be freely spun during a testing stage
following
substantial assembly of the timer so that the amount of time required for
timer
testing is greatly reduced.
The cam-operated timer apparatus and method that includes the above
aspects of the invention comprises the following. A housing having a base with
a
first open side, a second open side and details in the base pointing toward
the first
open side to accept cam-operated timer components. A cover enclosing the first
open side having details pointing toward the base to accept cam-operated timer
components. Timer components installed in the housing, comprising: a timer
drive
mechanism received by the base details, a motor connected to the timer drive
mechanism and received by the base details in an axis perpendicular to the
base,
and a camstack having three or more program blades carried on a shaft, driven
for
rotation by the timer drive mechanism, and received by details in the base in
an axis
perpendicular to the base.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 a shows an appliance known in the prior art;
FIG. 1 b shows an assembled cam-operated timer in accordance with
the invention;
FIG. 2 shows a housing base for the cam-operated timer shown in
FIG. 1 b;
FIGs. 3a-b show two other views of the housing base shown in FIG. 2;
FIG. 4a shows an exterior view of a first side cover to the housing base
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shown in FIG. 2;
FIG. 4b shows an interior view of a first side cover to
the housing base
shown in FIG. 2;
FIG. 5a shows an exterior view of a second side cover to
the housing
base shown in FIG. 2;
FIG. 5b shows an interior view of a second side cover to
the housing
base shown in FIG. 2;
FIG. 6 shows an exploded view of selected timer components
and the
housing base shown in FIG. 2;
FIG. 7 shows an exploded view of a motor and gear train
for the cam-
operated timer shown in FIG. 1b;
FIG. 8 shows an exploded view of a camstack for th
e cam-operated
timer shown in FIG. 1 b;
FIG. 9 shows an exploded view of blade switches and the
second side
over for the cam-operated timer shown in FIG. 1
b;
FIGs. 10a-b show views of the camstack without a controls shaft;
FIG. 11 shows a bottom view of the camstack;
FIGs. 12a-c show views of a drive cam;
FIGs. 13a-d show views of a primary drive pawl;
FIGs. 14a-d show views of a secondary drive pawl;
FIGs. 15a-b show the primary drive pawl and secondary drive
pawl at 0
degrees;
FIGs. 16a-b show the primary drive pawl and secondary drive
pawl at 6
degrees;
FIGs. 17a-b show the primary drive pawl and secondary drive
pawl at 12
degrees;
FIGs. 18a-b show the primary drive pawl and secondary drive
pawl at 18
degrees;
FIGs. 19a-b show the primary drive pawl and secondary drive
pawl at 24
degrees;
FIGs. 20a-b show the primary drive pawl and secondary drive
pawl at 30
degrees;
FIGs. 21a-b show the primary drive pawl and secondary drive
pawl at 80
degrees;
CA 02207543 1997-OS-28
"?
FIGs. 22a-b show the primary drive pawl and secondary drive pawl at 217
degrees;
FIGs. 23a-b show the primary drive pawl and secondary drive pawl at 260
degrees;
FIGs. 24a-b show the primary drive pawl and secondary drive pawl at 280
degrees;
FIGs.25a-b show the primary drive pawl and secondary drive
pawl at 320
degrees;
FIG. 26 shows a camstack drive advance graph;
FIGs.27a-b show a delay camstack pawl;
FIG. 28 shows a delay ratchet pawl;
FIG. 29 shows a delay no-back pawl;
FIGs.30 a-b show a delay drive wheel;
FIG. 31 shows a sectioned view of the delay drive wheel;
FIG. 32 shows a masking lever;
FIG. 33 shows a delay lifter;
FIG. 34 shows a delay rocker;
FIG. 35a shows a drive spring;
FIG. 35b shows a delay camstack pawl spring;
FIG. 35c shows a delay ratchet pawl spring;
FIG. 36 shows the delay drive operating;
FIG. 37 shows another view of the delay drive operating;
FIG. 38 shows the delay drive masked from operation; and,
FIG. 39 shows the delay drive advance graph.
DETAILED DESCRIPTION
Referring to FIGS. 1 b - 9, the cam-operated timer 52 incorporates principals
of Design For Manufacturing (DFM) and Design For Assembly (DFA). Under DFM
and DFA designing an apparatus is the first step in its manufacturing and
assembly. Design For Manufacturing involves considering how parts and
components will be manufactured when they are designed in order to reduce
manufacturing time, expense, waste, and improve quality Generally parts can be
manufactured better if their geometry is simple, there are as few parts as
possible,
and fasteners, retainers, guides, and bearings are integral to parts rather
than
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CA 02207543 1997-OS-28
separate components. Plastic parts can be manufactured better if they have
rounded corners, roughly consistent thickness, and draft angles to permit easy
extraction from molds. Use of plastic for parts can allow greater complexity
for a
single part than the use of metal thereby enabling parts reduction.
Design For Assembly (DFA) involves considering how parts will be
assembled into a product in order to reduce the number of parts and permit
easier
assembly of parts. An important aspect of DFA is to design parts that can be
handled and assembled more easily. Generally parts can be handled more easily
if parts can be assembled on a straight axis, there are only a few assembly
axes,
the part is oriented either parallel or perpendicular to the assembly axis,
the part
can only be assembled in the correct location, the target zone where the part
is to
be assembled is generous, the parts are radiused where they will contact other
parts during assembly to better guide the parts into the target, and the part
is
asymmetrical in both horizontal and vertical planes to permit automated
assembly
machines to better hold and orient parts. Design for assembly and design for
manufacturing are described in Machine Design, Design For Assembly, Penton
Education Division, 1100 Superior Avenue, Cleveland, Ohio 44114 (1984).
Referring to FIGs. 1 a-9, an appliance 50 such as a clothes washing
machine, clothes dryer, and dishwasher often uses a cam-operated timer 52 to
control various appliance functions in accordance with a predetermined
program.
The cam-operated timer 52 will typically be mounted in an appliance console on
a
console mounting plate 51 that has a control shaft bore and mounting slots.
The
cam-operated timer 52 includes a housing, and timer components. The timer
components include a motor, a gear train 60 (see FIG. 19), a camstack 62, a
camstack drive 64, blade switches 66, a master switch, a quiet cycle selector
, and
a subinterval switch. A more detailed description of the housing and timer
components follow.
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HOUSING
Referring to FIGS. 1 b-5, the housing includes a base 74, a first side cover
76, and a second side cover 78. The housing base 74 has a first open side 80,
a
second open side 82, a base platform 84, base details, a base assembly detail
88,
a base sealing ridge 90, base first side cover fasteners 92, base second side
cover fasteners 94, base plug rail 96, and a base mount. The first side cover
76
is installed over the first open side 80 of the housing base 74, and the
second side
cover 78 is installed over the second open side 82 of the housing base 74. The
base platform 84 carries the base details and provides a datum plane for
orienting
the housing and timer components. The housing is molded from a plastic such as
a mineral glass filled thermoplastic such as polyester polybutylene
terephthalate
(PBT). The housing base 74 is preferably molded to form a single piece of
plastic
with a draft angle of about 1.5° expanding toward the first open side
80.
The base details include base drive details, base motor details, base
camstack details , and base master switch details 148. The base details point
toward the first open side 80 to accept timer components, and the base details
are
orientated substantially perpendicular to the base platform 84. The base
details
perform one or more of the following functions: locate timer components in the
housing, retain timer components in the housing, and provide bearing surfaces
for
movement of timer components. The base details reduce the need for separate
fasteners, connectors and bearings which can complicate assembly, increase
quality defects, and create tolerance stack-up problems. The base details are
generally either radiused or tapered on surfaces nearest the first open side
80 to
provide a greater target area for the assembly of timer components and to
reduce
the opportunity for timer components to improperly seat during installation.
Since
the housing base 74 is preferably a single piece of plastic and the base
details are
integral to the base, assembly variations are greatly reduced. The use of
molded
base details reduces the number of parts required for the cam-operated timer
52.
The base drive details include a drive cam mount 102, a drive cam bore
104, a drive cam bore service mark 106, a drive spring mount 108, a
subinterval
pivot pin 110, a secondary drive pawl stop 112, a masking lever pivot pin 114,
delay spring support post 116, delay no-back spring seat 118, a delay rocker
pivot
pin 120, and delay wheel mount 122. The drive cam mount 102 inner diameter
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7
provides a bearing for rotation of the camstack drive 64. The drive cam bore
104
permits visual inspection of the drive cam 606 by a service person to
determine if
the camstack drive 64 is rotating. The drive cam bore service mark 106 on the
outside of the base 74 permits a service person to relate camstack drive
operation
to camstack rotation. The drive spring mount 108 positions the drive spring
612
about 0.040 of an inch (0.102 cm) above the base platform 84 for proper
biasing
of the camstack drive 64. The subinterval pivot pin 110 provides the
subinterval
switch an axis on which to pivot. The secondary drive pawl stop 112 limits
movement of the camstack drive 64. The masking lever pivot pin 114 provides a
pivot axis for a camstack drive component 680. The delay spring support post
116 provides a location on the housing base 74 to connect a camstack drive
component. The delay no-back spring seat 118 provides a surface to assist in
biasing a camstack drive component. The delay rocker pivot pin 120 provides a
pivot axis for a camstack drive component 672. The delay wheel mount 122
provides an axis for rotation of a camstack drive component. The delay wheel
mount 122 includes a delay wheel mount first bearing 124, a delay wheel mount
draft 126, and a delay wheel second bearing 128. The delay wheel mount first
bearing 124, the delay wheel mount draft 126, and the delay wheel mount second
bearing 128 provide dual bearing surfaces to reduce the draft angle of the
delay
wheel mount first bearing 124 and delay wheel mount second bearing 128
compared to the overall draft angle of the delay wheel mount 122.
The base motor details include a motor shelf 132, motor pedestals 134,
motor pedestal ribs 136, and base motor fasteners 138. The motor shelf 132 and
motor pedestals 134 cooperate to locate the motor (see FIG. 7) about 1.19
inches
(3.023 cm) above the base platform 84. The motor pedestal ribs 136 vertically
locate a camstack drive component. The base motor fasteners 138 are
chambered to provide a larger target area to more easily align with the motor
during installation and then after the motor is installed the base motor
fasteners
138 are heat staked to attach the motor to the housing base 74.
The base camstack details include a control shaft mount 142, a hub
opening 144, and camstack supports 146. The control shaft mount 142 outer
diameter serves as a bearing for rotation of the camstack 62. The hub opening
144 permits insertion of a camstack component during assembly of the cam-
operated timer 52. The camstack supports 146 carry the camstack 62 and are
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CA 02207543 1997-OS-28
radiused to reduce friction between the camstack supports 146 and locate the
camstack 62 about 0.360 of an inch (0.914 cm) above the base platform 84.
The base master switch details 148 include a rocker lifter pivot pin 150, a
rocker lifter retainer 152, a rocker lifter bearing 154, a switch lifter
offset 156, a
switch lifter pivot pin 158, a switch lifter retainer 160, a switch lifter
bearing 162, a
rocker support 164, a rocker cradle 166, and a lift bar channel 168. The
rocker
lifter pivot pin 150 and switch lifter pivot pin 158 locate master switch
components
on the base platform 84 and provide a pivot axis for master switch components.
The switch lifter offset 156 positions a master switch component about 0.055
of an
inch (0.140 cm) above the base platform 84 to provide clearance for the
subinterval switch. The rocker lifter bearing 154 and switch lifter bearing
162 are
raised portions of the base platform 84 that provide bearing surfaces to
reduce
friction during movement of master switch components. The rocker lifter
retainer
152 and switch lifter retainer 160 are hook-shaped and integral to the base
platform 84 to maintain proper alignment of master switch components in
relation
to the base platform 84 . The rocker support 164 locates a master switch
component about 0.865 of an inch (2.197 cm) above the base platform 84, and
the
rocker cradle 166 provides a pivot axis and bearing surface for a master
switch
component. The lift bar channel 168 locates a master switch component and
provides an axis and bearing movement for the master switch component.
The base assembly detail 88 is an assembly mount that is used during
assembly of the cam-operated timer 52. The base assembly detail 88 is a
circular
bore in the housing base 74 that mates with automated assembly equipment such
as a palette-and-free assembly detail (not shown). During assembly of the cam-
operated timer 52, the base assembly detail 88 helps to locate and hold the
housing base 74 in an assembly palette for automated or manual assembly of the
cam-operated timer 52.
The base sealing ridge 90 cooperates with the first side cover 76 to reduce
the opportunity for contamination to enter the housing between the base 74 and
first side cover 76. The base first side cover fasteners 92 cooperate with the
first
side cover 76 and are heat staked to attach the first side cover 76 to the
base 74.
The base second side cover fasteners 94 include a base second side cover pin
170 (see FIG. 3a), a base female wafer fastener 172 (see FIG. 2), and a base
female wafer ramp 174 that cooperate with second side cover 78 to attach the
CA 02207543 1997-OS-28
7
second side cover 78 to the base 74. The base plug rail 96 aligns and guides
an
electrical plug (not shown) to mate with the blade switches 66. The base plug
rail
96 improves alignment of the electrical plug with the blade switch 66 to
improve
electrical connections and reduce the opportunity for damage to the electrical
plug
and blade switches 66.
The base 74 is mounted to an appliance by first mounting tabs 176, a
second mounting tab 178, a locking pin support 180, and a screw mount 182
hereinafter collectively referred to as "the base mount'°. The base
mount
cooperates with the first side cover 76 to attach the cam-operated timer 52 to
an
appliance console mounting plate 51 (see FIG. 1 a). The first mounting tabs
176
and second mounting tab 178 are radiused to ease insertion into appliance
console mounting slots. The second mounting tab 178 includes a second
mounting tab slot that receives a portion of the console mounting plate 51 to
secure the portion of the base nearest the second mounting tab slot to the
mounting plate. The locking pin support 180 cooperates with the first side
cover
76 to lock the cam-operated timer 52 on the mounting plate. The screw mount
182 is for a screw (not shown) that can be used as an additional means to
secure
the cam-operated timer 52 to the appliance console.
The first side cover 76 (see FIGs. 4a, 4b) first side cover fasteners 186, a
first side cover lip 188, and a first side cover locking pin 190. The first
side also
includes a camstack hub bore 192, a camstack hub bearing 194, a cover mounting
recess 196, a detent follower channel 198. The first side cover 76 also
includes
cover motor details, and cover master switch details, as will be discussed
below.
The camstack hub bore 192 permits a portion of the camstack 62 to extend
through the first side cover 76. The camstack hub bearing 194 provides both a
rotational bearing and a thrust bearing for the camstack 62. The camstack hub
bore 192 is not chambered to increase camstack hub bearing 194 strength. The
cover mounting recess 196 permits an appliance mechanical fastener such as a
screw (not shown) to have clearance without damaging the cam-operated timer
52. The detent follower channel 198 has a detent follower bore 200 and a
detent
spring pilot 202. The detent follower channel 198 and detent spring pilot 202
provide an axis for movement and assist in retaining timer components that
engage the camstack 62.
The cover motor details include cover gear arbor sockets 208, a cover
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CA 02207543 1997-OS-28
motor shaft socket 210, a cover spline connector bore 212, and a cover gear
train
partition 214. The cover gear arbor sockets 208 extend about 0.149 of an inch
(0.378 cm) from the first side cover 76 and have a chamber lead-in of about
45° to
increase the target area for assembly of the first side cover 76 over the
housing
base 74. The cover motor shaft socket 210 extends about 0.433 of an inch
(1.100
cm) from the first side cover 76 and also has a chamber lead-in of about
45° to
increase the target area for assembly of the first side cover 76 over the
housing
base 74. The cover gear train partition 214 serves to isolate most of the gear
train 60 in the housing.
The cover master switch details include a cover first lift bar guide 216, a
cover second lift bar guide 218, cover lift bar bearings 220, and a cover
rocker
retainer 222. The cover first lift bar guide 216 and the cover second lift bar
guide
218 cooperate to axially align a master switch component. The lift bar
bearings
220 provide bearing surfaces for smooth movement of a master switch
component. The cover rocker retainer 222 cooperates with the housing base
rocker support 164 to secure a master switch component in the housing base 74
when the first side cover 76 is installed.
The first side cover fasteners 186 include first side cover attachment bores
224, a cover female wafer fastener 226, and a cover female wafer ramp 228. The
first side cover attachment bores 224 receive complementary base first side
cover
fasteners 92 to align and attach the firsfi side cover 76 to the base 74. The
first
side cover attachment bores 224 are chambered to provide a greater target area
when the first side cover 76 is attached to the housing base 74. The cover
female
wafer fastener 226 receives a complimentary fastener from the blade switches
66.
The cover female wafer ramp 228 provides a greater target area and eases
attachment of the complimentary fastener from the blade switches 66. Use of
plastic permits the first side cover 76 to be heat staked to the base 74 to
eliminate
the need for separate fasteners such as screws or rivets. The first side cover
lip
188 extends around a portion of the periphery of the first side cover 76 to
create a
seal between the first side cover 76 and the base 74. The first side cover
locking
pin 190 engages a complementary fastener on an appliance console mounting
plate 51 to assist in securing the cam-operated timer 52 into an appliance
console.
The base locking pin support 180 cooperates with the first side cover locking
pin
190 to protect the first side cover locking pin 190 by limiting its flexing.
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The second side cover 78 (see FIGs. 5a, 5b) includes, a wafer mount 230,
a plug connector 232, second side cover fasteners, which are described below,
and second side cover assembly bores 236. The wafer mount 230 cooperates
with the second side cover assembly bores 236 to attach the blade switch 66 in
the second side cover 78. The wafer mount 230 includes a wafer shelf 238,
wafer
mounting bores 240, and wafer rivets 242 (see FIG. 9). The wafer shelf 238
aligns and stabilizes the blade switches 66 in the second side cover 78. Wafer
rivets 242 are then installed through the blade switches 66 and the wafer
mounting
bores 240 to secure the blades switches 66 into the second side cover 78. The
plug connector 232 has plug guides 244 and a ramped surface 246. The plug
guides 244 cooperate with the electrical plug (not shown) to properly align
the
electrical plug with the blade switches 66. When the electrical plug is seated
on
the blade switches 66, the ramped surface 246 engages the electrical plug to
lock
the electrical plug on the second side cover 78. The second side cover
fasteners
include a second side cover attachment bore 248, a second side cover base pin
250, and a second side cover ramp pin 252. The second side cover fasteners are
used to attach the second side cover 78 to the housing base 74 and first side
cover 76. The second side cover attachment bore 248 engages the base second
side cover pin 170 (see FIG. 3a) which is then heat staked to provide an
additional
means of attaching the second side cover 78 to the base 74. The second side
cover assembly bores 236 are used as an assembly aid when attaching the blade
switches 66 and as an assembly aid when attaching the second side cover 78 to
the housing base 74 and first side cover 76.
An advantage of having a plastic timer housing with all timer components
contained inside the plastic timer housing is that the cam-operated timer 52
is
electrically insulated from the appliance 50 eliminating the need for a ground
strap.
Another advantage of the electrically insulated plastic housing is that
integral
plastic attachments can easily be added to the plastic housing that are
designed
to cooperate with plastic attachments on. the appliance control console to
permit
the cam-operated timer 52 to be snapped into the appliance 50 rather than be
attached with separate fasteners.
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MOTOR
Referring to FIG. 7, the motor comprises a field plate 254, a stator cup 256,
a bobbin 258, a rotor 260, and motor terminals 262. The motor transmits torque
through the gear train 60 to rotate the camstack drive 64 (see FIG. 6). The
motor
is an AC synchronous motor designed to operate on about 120 ~/AC at about 50-
60 Hz to produce rotor rotation of about 600 RPM at a torque of about 100
ounce-
inches (0.072 KgM) measured at 1.0 R.PM. A separate enclosure for the motor is
not necessary because the motor is enclosed by the housing thus double
insulating the motor. The motor is placed at a mid-level in the housing with
the
gear train 60 above the motor and the camstack drive below the motor. The
motor terminals 262 permit the motor to be electrically connected to the blade
switches 66 when the second side cover 78, carrying the blade switches 66, is
attached to the housing.
The field plate 254 has stator poles 264, a rotor cavity 266, a field plate
bearing 268, stator cup slots 270, gear arbor bores 272, a field plate
terminal
block mount 274, and field plate attachment bores 276. The field plate stator
poles 264 are formed from material lanced and bent to form the rotor cavity
266.
Also by bending the stator poles 264 from rotor cavity material, the stator
poles
264 are curved toward the rotor cavity 266 which reduces the chance of the
rotor
260 becoming caught on a stator pole during installation. The field plate
bearing
268 is a sleeve bearing, integral to the field plate 254, that is extruded
toward the
housing base platform 84 to permit easier installation of a gear train
component.
The housingless motor is a factor that permits use of field plate bearing 268.
The field plate terminal block mount 274 has a first prong 278 and a second
prong 280 that engage the motor terminals 262 to align and support the motor
terminals. The field plate terminal block mount 274 aligns the motor terminals
262
in relation to the field plate 254. Since the field plate 254 is attached to
the
housing base 74, the motor terminals 262 are also aligned in relation to the
housing base 74 and the second open side 82. The field plate terminal block
mount 274 supports the motor terminals 262 in both a plane parallel to the
housing base platform 84 and in a plane perpendicular to the housing base
platform 84. There is a space of about 0.050 of an inch (0.127 cm) between the
first prong 278 and the second prong 280 that the motor terminals 262 engage
to
14
CA 02207543 1997-OS-28
strengthen the motor terminals 262 and to maintain a proper alignment angle
between the motor terminals 262 and the blade switches 66 attached to the
second side cover 78. The ends of the first prong 278 and second prong 280 are
tapered and engage the motor terminals 262 to substantially prevent axial
displacement of the motor terminals 262 when the second side cover 78,
carrying
the blade switches 66, is installed on the housing.
The field plate attachment bores 276 coincide with the base motor fasteners
138 (see FIG. 2) to align the field plate 254 in the housing base 74. The base
motor fasteners 138 are staked to the field plate attachment bores 276 to
secure
the field plate 254 to the housing base 74 to withstand about a 50.0 Ib.
(22.68 Kg)
pull-off force without loosening. The field plate 254 serves multiple
purposes: the
field plate 254 provides a means for attaching the motor subassembly to the
housing base 74; the field plate 254 carries the gear train 60; the field
plate 254
provides a bearing for a gear train component 260, and the field plate 254
provides a motor terminal mount. The field plate 254 is stamped from a low
carbon steel with good magnetic properties.
The stator cup 256 includes stator poles 282, a rotor shaft bore 284, a
bobbin terminal port 286, and stator cup tabs 288. The stator cup poles 282
are
formed from material outside the rotor cavity 266. The bobbin terminal port
286
provides an opening in the stator cup 256 for the portion of the bobbin 258
carrying the motor terminals 262 to extend through the stator cup 256. After
insertion, the stator cup tabs 288 are staked to the field plate stator cup
slots 270
to secure the stator cup 256 to the field plate 254. The stator cup 256 is
stamped
from a low carbon steel which is preferably the same material used for the
field
plate 254.
The bobbin 258 includes bobbin winding lugs 290, a bobbin reverse winding
post 292, bobbin stator notches 294, and magnet wire 296. The bobbin winding
lugs 290 are used to rotate the bobbin 258 when magnet wire 296 is wound onto
the bobbin 258. The bobbin reverse winding post 292 is used to reverse the
winding direction of the magnet wire 296, and has a radiused top to reduce the
probability of interference with winding. The bobbin stator notches 294 align
the
bobbin 258 with stator cup poles 264 when the bobbin 258 is installed in the
stator
cup 256 prior to the stator cup being staked to the field plate 254. The
bobbin
258 is preferably manufactured from a 30% glass filled nylon 6/6.
CA 02207543 1997-OS-28
The magnet wire 296 is typicall~r 43-48 auge copper, and about 10,000 turns
are placed on the bobbin 258. The magnet wire 296 has ends that are skeined
with seven skeins for about five inches for added strength to reduce breaks
that
can occur when the magnet wire 296 is attached to the bobbin 258 and the motor
terminals 262. Winding of the bobbin 258 can be done in a single direction for
all
winding or some winding can be counter wound by using the bobbin reverse
winding post 292 to reverse the direction of winding. Counter winding permits
the
excitation level of the bobbin to be balanced with other factors such as rotor
inertia
and power consumption when using larger gauge, less expensive wire such as 40-
50 gauge wire. The number of counter-wound turns to adjust motor excitation E
as measured in ampere-turns is defined in terms of relation current I and the
number of turns of magnet wire N by the following formula: E = I (N FoRwaRO -
2N
REVERSE
The rotor 260 includes a rotor shaft 298, a rotor support 300, a molded
magnet 302, a no-back cam 304, and a rotor gear 306. The rotor shaft 298 is
inserted into the rotor shaft bore 284 and staked to the stator cup 256. The
top of
the rotor shaft 298 is slightly tapered to ease installation of the rotor 260
over the
rotor shaft 298. The rotor support 300 has a rotor support first end 301 and a
rotor support second end 303. The rotor support first end 301 is chambered to
fit
more easily over the rotor shaft 298. The rotor support second end 303 extends
beyond the rotor gear 306 to serve as a thrust bearing against the first side
cover
motor arbor socket. The molded magnet 302 is preferably an injection molded
polymer bonded ferrite. A synthetic lubricant such as Nye~ 723 is placed on
the
rotor shaft 298 to reduce friction. The rotor support is preferably molded
from a
liquid crystal polymer. The rotor gear 306 has ten teeth for 60 Hz
applications
twelve teeth for 50 Hz applications to produce about the same rotational speed
to
the first stage gear.
The motor terminals 262 include a motor terminal block 308 and motor
terminal wires 310. The motor terminal block 308 includes terminal block ribs
312,
a magnet wire guide 314, a magnet wire post 316, motor terminal sockets 318,
terminal wire channels 320, center motor terminal guide 322, and side motor
terminal guides 324. The terminal block ribs 312 extend about 0.169 of an inch
(0.429 cm) from the motor terminal block 308 and engage the field plate
terminal
block mount 274 to secure the motor terminal block 308 to the field plate 254
and
16
CA 02207543 1997-OS-28
align the motor terminal block 308 in relation to the housing base 74 and
second
open side 82. The bobbin 258 which is integral with the motor terminal block
308
also assists in securing the motor terminal block 308 to the field plate 254.
More
specifically, the terminal block ribs 312 cooperate with the field plate
terminal block
first prong 278 and second prong 280 to support and align the motor terminals
262
both in a plane parallel to the housing base platform 84 and in a plane
perpendicular to the housing base platform 84. Proper alignment and support of
the motor terminals 262 is necessary for the motor terminals 262 to mate with
the
target area of the blade switches during assembly of the blade switches 66
carried
in the second side cover 78.
The magnet wire guide 314 is a channel about 0.030 of an inch wide (0.076
cm) and about 0.060 of an inch deep (0.152 cm) to route the magnet wire 296
from the bobbin 258 to the motor terminal wires 296. The magnet wire post 316
cooperates with the motor terminal block 308 to create a channel to guide the
magnet wire 296 from the bobbin 258 to the motor terminal wires 296. The
magnet wire post 316 is radiused to reduce the opportunity for magnet wire 296
to
become snagged during connection of the magnet wire to the motor terminals
262.
The motor terminal sockets 318 receive the motor terminal wires 262 and
are circular with a diameter of about 0.0355 inch (0.0902 cm). The terminal
wire
channels 320 serve as an alignment aid during installation of the motor
terminal
wire 262. When the motor terminal wires 262 are installed in the terminal wire
channels 320, the terminal wire channels 320 increase the rigidity of the
motor
terminal wires 262 and maintain parallel alignment of the motor terminal wire
310.
The terminal wire channels 320 are about 0.054 of an inch (0.137 cm) wide and
about 0.031 of an inch (0.079 cm) deep.
The center motor terminal guide 322 and side motor terminal guides 324
function to align the motor terminals 262 with the blade switches 66 when the
second side cover 78 is installed onto the housing base 74. The center male
guide 322 extends about 0.225 of an inch (0.572 cm) above the motor terminal
block 308 and narrows away from the motor terminal block 308 to ease insertion
into the blade switches 66. When the second side cover 78 is assembled onto
the
housing base 74, the center motor terminal guide 322 assists in locating the
motor
terminals 262 in relation to the blade switches 66. The side motor terminal
guides
324 extend about 0.100 of an inch (0.254 cm) and narrow away from the motor
17
CA 02207543 1997-OS-28
terminal block 308 to ease insertion into the blade switches 66. When the
second
side cover 78 is assembled onto the housing base 74, the side motor terminal
guides 324 also assist in locating the motor terminals 262 in relation to the
blade
switches.
The motor terminal wires 262 include motor terminal wire coil ends 326 and
motor terminal wire blade switch ends 328. The motor terminal wires 262 are
preferably formed from a 0.031 inch (0.0787 cm) square phosphor bronze 510
alloy with a 0.003 inch (0.00762 cm) maximum radius on the corners that is pre-
tined with a solder. The motor terminal wire straight length is about 0.795 of
an
inch (2.019 cm), and both the motor terminal wire coil end 326 and the motor
terminal wire blade switch end 328 are cut with a 60° pyramid angle
swage. The
motor terminal wire coil end swage provides an insertion guide for inserting
the
motor terminals 262 into the motor terminal sockets 318. The motor terminal
wire
blade switch end swage provides an insertion aid to guide the motor terminal
wire
switch ends 328 into the blade switches 66 during installation on the second
side
cover 78. The terminal blade switch end 328 extends about 0.170 inches (0.432
cm) above the motor terminal sockets.
The motor terminal wires 262 are installed in the motor terminal sockets
318 as follows. The motor terminal wires 262 are inserted into the motor
terminal
sockets 318 prior to the bobbin 258 being wound with magnet wire 296. The
motor terminal wires 262 are secured in the terminal sockets 318 by
interference
between square motor terminal wires 262 and the round terminal sockets 318.
After the motor terminals 262 are inserted, the terminal blade switch ends 328
are
bent at about 90°, so the motor terminal wire switch ends are received
in the
terminal wire channels 320. The terminal wire channels 320 align and increase
the rigidity of the motor terminal wire switch ends. After the magnet wire is
attached to the motor terminal wire coil ends and soldered, the motor terminal
wire
coil ends 326 are bent at an acute angle with a roller to reduce damage to the
magnet wire and to prevent the coil ends from interfering with the first side
cover
detent follower channel 198.
The motor is assembled before installation into the housing base 74 by
assembling motor components on a straight axis that is perpendicular to the
field
plate 254 using automated assembly equipment. Assembly of the motor begins by
staking the rotor shaft 298 to the stator cup rotor shaft bore 284. Gear train
18
CA 02207543 1997-OS-28
1
1 f
components are then staked to the field plate gear arbor bores 272. After
staking,
the gear arbors 330 may be lubricated lightly to prevent corrosion. The motor
terminal wires 262 are inserted into the motor terminal sockets 318 and bent
so
that the motor terminal wire switch ends 328 are carried in the terminal wire
channels 320. The bobbin 258 is wound with wire 296 and the wire is attached
to
the motor terminal wire coil ends 326. The bobbin 258 is placed into the
stator
cup 256, and the stator cup is attached to the field plate 254. When the
stator cup
256 is attached to the field plate 254, the terminal block ribs 312 engage the
field
plate terminal block mount 274, to align and secure the motor terminal block
308
to the field plate. The rotor shaft 298 is lubricated with a synthetic
hydrocarbon
such as Nye~ 723GR, and the rotor support 300 is placed over the rotor shaft
298. Gear train components are installed on the field plate 254 and lubricated
to
reduce noise during operation. The assembled motor is then placed on base
motor details and the base motor fasteners 138 are heat staked to secure the
motor module in place, and the rotor 260 is then placed over the rotor shaft
298.
19
CA 02207543 1997-OS-28
t
GEAR TRAIN
Referring to FIG. 7, the gear train 60 includes gear arbors 330, gears 332,
and a spline connector 334. The gear train 60 transmits approximately 100 inch
ounces (0.072 KgM) of torque at 1.0 RPM as measured at the camstack drive 64
from the motor and in the process reduces the rotational speed of the motor
and
increases its torque. The gears 332 can be selected to change the overall gear
train ratio from about 250:1 to 1800:1 which represents rotational speeds from
about 2.4 RPM to 0.3 RPM. Since the gear train 60 is located inside the
housing,
a separate housing for the gear train 60 is not required. The gear arbors 330
include a first stage gear arbor 336, a second stage gear arbor 338, a third
stage
gear arbor 340, and a fourth stage gear arbor 342. The gear arbors 330 are
staked to the motor field plate gear arbor bores 272. When the motor
subassembly is installed in the housing base 74 and the frst side cover 76 is
attached to the housing base 74, the cover gear arbor sockets 208 engage the
gear arbors 330 to help retain and maintain proper gear arbor alignment. The
gear arbors 330 are about 0.590 of an inch (1.499 cm) long and manufactured
from hardened steel. Once installed, the gear arbors 330 are coated with a
lubricant to reduce corrosion.
The gear train is divided into first level gears, second level gears, and
third
level gears. The gears 332 include a first stage gear 344, a second stage gear
360, a third stage gear 372, a fourth stage gear 384, and an output gear 396,
all
manufactured from a material such as acetal copolymer. Each of the gears 332
has a pinion gear and an outer gear. The gears 332 have an involute spline
profile to provide more radiused surfaces for meshing than in some other types
of
profiles. The gears 332 are also configured with a predetermined amount of
backlash to facilitate meshing, and the gears 332 are permitted to cant
slightly
when on the gear arbors 330 to facilitates meshing. The first level gears,
second
level gears and third level gear are constructed on three different meshing
levels,
a lower level, a middle level, and an upper level, so that the gears can be
installed
in some gear train configurations with only two gears meshing at a time during
assembly Assembly of the gear train 60 with only two gears meshing at a time
is
easier and less complicated than assembly of a gear train 60 requiring more
than
two gears to mesh at a time. In other gear trains the third stage gear 372 may
be
CA 02207543 1997-OS-28
i
required to mesh a total of three gears during assembly, i.e., the third stage
gear
372 may be required to mesh with both the second stage gear 360 and the fourth
stage gear 384 at the same time. The gears 332 are color coded for easy
identification with colors such as white, blue, green, and orange.
The first stage gear 344 has a first stage base thrust bearing (not shown), a
first stage no-back recess (not shown), a first stage no-back lever 350, a
first
stage bore 352, a first stage pinion 354, a first stage outer gear 356, and a
first
stage top thrust bearing 358. The first stage base thrust bearing provides a
surface for frictional contact with the field plate 254 when the first stage
gear 344
is installed on the first stage gear arbor 336. The first stage no-back recess
(not
shown) is a cavity to accept the first stage no-back lever 350. The first
stage no-
back lever 350 is attached to the outer diameter of the first stage thrust
bearing
and carried in the first stage no-back recess 348, so the first stage thrust
bearing
can still provide a surface for frictional contact with the field plate 254
once the
first stage no-back lever 350 is installed on the first stage gear 344. The
first
stage no-back lever 350 is attached to the first stage gear 344 prior to the
first
stage gear 344 being installed on the first stage gear arbor 336. The first
stage
no-back lever 350 cooperates with the rotor no-back cam 304 to ensure the
motor
will only operate in one direction. The first stage no-back lever 350 is
preferably
manufactured from an acetal copolymer. The first stage bore 352 cooperates
with
the first stage arbor 336 to provide a low friction axis of rotation for the
first stage
gear 344. The first stage bore 352 has about a 45° chamber to provide a
greater
target area when the first stage bore 352 is placed over the first stage gear
arbor
336. The first stage outer gear 356 is driven by the rotor gear 306, and the
first
stage pinion 354 drives the second stage gear 360. The first stage top thrust
bearing 358 provides a frictional surface to contact the corresponding first
side
cover gear arbor socket when the cam-operated timer 52 is assembled. When the
first stage gear 344 with attached first stage no-back lever 350 is installed
over the
first stage gear arbor 336, the first stage no-back lever 350 is oriented to
rotor
cavity side toward the motor terminals 262 for the motor to operate clockwise.
If
the first stage gear 344 with attached first stage no-back lever 350 is
oriented to
the rotor cavity side away from the motor terminals 262, the motor will rotate
counter-clockwise.
The second stage gear 360 has a second stage base thrust bearing 362, a
21
CA 02207543 1997-OS-28
second stage bore 364, a second stage pinion 366, a second stage outer gear
368, and a second stage top thrust bearing 370. The second stage base thrust
bearing (not shown) provides a surface for frictional contact with the field
plate 254
when the second stage gear 360 is installed on the second stage gear arbor
338.
The second stage bore 364 cooperates with the second stage arbor 338 to
provide a low friction axis of rotation for the second stage gear 360. The
second
stage bore 364 has about a 45° chamber to provide a greater target area
when
the second stage bore 364 is placed over the second stage gear arbor 338. The
second stage outer gear 368 is driven by the first stage pinion 354, and the
second stage pinion 366 drives the third stage outer gear 380. The second
stage
top thrust bearing 370 provides a frictional surface to contact the
corresponding
second side cover gear arbor socket when the cam-operated timer 52 is
assembled.
The third stage gear 372 has a third stage base thrust bearing 374, a third
stage bore 376, a third stage pinion (hidden from view), a third stage outer
gear
380, and a third stage top thrust bearing 382. The third stage base thrust
bearing
374 provides a surface for frictional contact with the field plate 254 when
the third
stage gear 372 is installed on the third stage gear arbor 340. The third stage
bore
376 cooperates with the third stage gear arbor 340 to provide a low friction
axis of
rotation for the third stage gear 372. The third stage bore 376 has about a
45°
chamber to provide a greater target area when the third stage bore 376 is
placed
over the third stage gear arbor 340. The third stage outer gear 380 is driven
by
the second stage pinion 366, and the third stage pinion drives the fourth
stage
outer gear 392. The third stage top thrust bearing 382 provides a frictional
surface to contact the corresponding third side cover gear arbor socket when
the
cam-operated timer 52 is assembled.
The fourth stage gear 384 has a fourth stage base thrust bearing (not
shown), a fourth stage bore 388, a fourth stage pinion (hidden from view), a
fourth
stage outer gear 392, and a fourth stage top thrust bearing 394. The fourth
stage
base thrust bearing provides a surface for frictional contact with the field
plate 254
when the fourth stage gear 384 is installed on the fourth stage gear arbor
342.
The fourth stage bore 388 cooperates with the fourth stage arbor 342 to
provide a
low friction axis of rotation for the fourth stage gear 384. The fourth stage
bore
388 has about a 45° chamber to provide a greater target area when the
fourth
22
CA 02207543 1997-OS-28
stage bore 388 is placed over the fourth stage gear arbor 342. The fourth
stage
outer gear 392 is driven by the third stage pinion, and the fourth stage
pinion
drives the output gear 396. The fourth stage top thrust bearing 394 provides a
frictional surface to contact the corresponding first side cover gear arbor
socket
when the cam-operated timer 52 is assembled.
The output gear 396 has an output extension 398, an output base thrust
bearing 400, an output base lead-in (hidden from view), an output gear
disconnect
bearing 404, an output gear rotational bearing (hidden from view), an output
field
plate thrust bearing (hidden from view), an output gear spline bore 410,
output
gear splines 412, output gear spline tips 414, an output spline connector
groove
416, and an output cover thrust bearing 418. The output gear 396 functions to
operate the drive cam 606 (see FIG. 6) for rotation and retain and maintain
proper
alignment of some camstack drive components. The output extension 398
extends through the motor field plate 254 to retain and maintain proper
alignment
of some camstack drive components. The output gear thrust bearing 400 engages
the secondary drive pawl 610 on the drive cam 606 to assist in locating and
securing the camstack drive 64 in the housing base 74. The output base lead-in
has a larger diameter than the drive cam top 630 to provide a larger target
area
for guiding the output gear 396 onto the drive cam 606. The output gear
disconnect bearing 404 engages the drive cam disconnect bearing 631 to permit
the output gear 396 to rotate independently of the drive cam 606 until a
spline
connector 334 is installed. The output gear rotational bearing engages the
field
plate bearing 268 to provide a rotational axis for the output gear 396. The
output
field plate thrust bearing engages the field plate 254 to properly space the
output
gear 396 in relation to the field plate 254 and provide a frictional surface
for the
output gear 396 to contact the field plate 254. The output spline bore 410
provides
space to receive the spline connector 334 and the output gear disconnect
bearing
404 provides a stop to prevent the spline connector 334 from migrating into
the
output extension 398. The output gear splines 412 provide a means to
frictionally
couple the output gear 396 to the spline connector 334. The output gear spline
tips 414 have about a 45° point to assist in synchronizing the output
gear 396 with
the spline connector 334 during installation of the spline connector 334. The
output spline connector groove 416 assists in carrying the spline connector
334.
The output cover thrust bearing 418 cooperates with the first side cover 76 to
23
CA 02207543 1997-OS-28
provide a frictional surface for contact with output gear 396 to assist in
retaining
the output gear 396 in the housing.
The drive connector 334, also referred to as a spline connector, includes a
spline connector lead-in 420, internal connector spline tips 422, internal
connector
splines 424, external connector spline tips 426, external connector splines
428,
spline connector locking fingers 430, and a spline connector assembly aid 432.
Without the spline connector installed, the output gear 396 can rotate on its
output
gear disconnect bearing 404 independently of the camstack drive 64 to permit a
test fixture to operate the camstack drive 64 to test operation of the blade
switches 66. Once the spline connector 334 is installed, the output gear 396
is
directly coupled to the camstack drive 64 for cam-operated timer operation.
The spline connector lead-in 420 extends beyond the internal connector
spline tips 422 and external connector spline tip 426 to provide a larger
target
area that does not require meshing to align the spline connector 334 with the
camstack drive 64 during installation. The internal connector spline tips 422
and
external connector spline tips 426 are tapered to about a 45° point to
ease
installation of the spline connector 334 by providing a larger meshing target
area.
The internal connector splines 424 cooperate with the camstack drive 64 to
provide a mechanical connection between the spline connector 334 and the
camstack drive 64. The external connector splines 428 cooperate with the
output
gear splines 412 to provide a mechanical connection between the spline
connector
334 and the output gear 396. The spline connector locking fingers 430 are
cantilever springs that create a larger outer diameter than the external
connector
splines 428. During installation through the first side cover spline connector
bore
212, the locking fingers contract to permit insertion through the first side
cover
spline connector bore 212 and then the locking fingers expand to capture the
spline connector 334 in the housing. When the spline connector 334 is
installed in
the output gear spline bore 410, the output spline connector groove 416
provides
clearance for the locking fingers to expand. The output gear disconnect
bearing
404 provides a stop for the spline connector lead-in 420 to contact to prevent
the
spline connector 334 from migrating into the output extension 398. The spline
connector assembly aid 432 cooperates with a tool during automated or manual
installation to facilitate insertion of the spline connector 334 through the
first side
cover 76 and into the output gear 396. The fit between the spline connector
334
24
CA 02207543 1997-OS-28
and the output gear spline bore 410 is preferably toleranced to permit the
spline
connector 334 to float to reduce the opportunity for the camstack drive 64 to
bind
during temperature and humidity excursions.
The gear train 60 is not fully assembled until the motor is installed in the
housing base 74 and secured by heat staking to prevent damage to gears by high
temperature heat used in the staking procedure. Although, the first stage gear
with attached no-back lever is installed on the first stage arbor prior to the
motor
being installed into the housing base 74. A more detailed description of gear
train
assembly is provided in a subsequent section titled "Assembly Of The Cam-
Operated Timer".
CAMSTACK
Referring to FIGS. 8, 10a-b, and 11, the camstack 62 includes a camstack
hub 434, camstack profiles 436, a control shaft 438, a clutch 440, and a cycle
selector detent 442. The camstack 62 is drum shaped and carries information
encoded on camstack profiles 436 to open and close the blade switches 66 in
accordance with a predetermined appliance program. The camstack hub 434
cooperates with the control shaft 438 to provide a rotational axis for the
camstack
62. The camstack 62 is driven for rotation by the camstack drive 64 which is
connected through the gear train 60 to the motor. The camstack 62 can be
manually rotated by an appliance operator using the control shaft 438 to
select an
appliance cycle. The camstack 62 is preferably manufactured from a mineral or
glass filed polypropylene.
The camstack hub 434 includes a center web 444, a clutch cavity 446, a
clutch shelf 448, clutch fasteners 450, a hub extension 452, hub extension
grooves 454, a hub control dial positioned 456, a hub bore 458, a hub inner
bearing 460, a hub displacement stop 462, and a hub outer bearing 464. The
center web 444 connects the camstack hub 434 to the camstack profiles 436. The
clutch cavity 446 provides residential space to house the clutch 440
internally to
the camstack 62. The clutch shelf 448 extends around the perimeter of the
clutch
cavity 446 to form a stable platform to receive a clutch component. The clutch
fasteners 450 are heat staked after the clutch 440 is installed in the
camstack 62
to capture the clutch 440 and the control shaft 438 within the hub bore 458.
The
hub extension 452 extends through the first side cover camstack hub bore when
CA 02207543 1997-OS-28
the camstack 62 is assembled in the cam-operated timer 52. The hub extension
452 also typically extends through an appliance console. The hub control dial
positioned 456 can carry a dial to communicate appliance cycle information to
an
appliance operator. The hub inner bearing 460 cooperates with the control
shaft
438 to provide a bearing for rotation of the camstack 62 on the control shaft
438.
The hub displacement stop 462 cooperates with the control shaft 438 to limit
the
travel of the control shaft 438 within the camstack 62 when the control shaft
is
indexed out to an extended position away from the housing base 74 by an
appliance operator. The hub outer bearing 464 cooperates with the control
shaft
438 to provide a second bearing for rotation of the camstack 62 on the control
shaft 438.
The camstack profiles 436 include switch program blades 466, a drive
surface 474, a detent blade 484, a camstack face 486, a delay profile 488, and
blade valleys 490. The switch program blades 466 carry appliance program
information to operate the blade switches 66 to make or break electrical
contacts
744 to switch appliance functions "on" and "off'. Examples of appliance
functions
that can be switched are hot and cold water valves, motor control circuits,
water
pump circuits, cam-operated timer motor control circuits, appliance motor
start
circuits, appliance motor run circuits, and to bypass circuits. The switch
program
blades 466 have an appliance program encoded on a top radius 468, a neutral
radius 470, a bottom radius 472. In cam-operated timer configurations without
the
optional master switch, the camstack profiles 436 can be configured to break
all
electrical contacts 744 of the blade switches 66 to turn "off' an appliance 50
such
as a dishwasher.
The drive blades 474 include a primary drive blade 476, a secondary drive
blade 478, a delay drive blade 480, and drive teeth 482. The primary drive
blade
476 and secondary drive blade 478 are engaged by the camstack drive 64 to
rotate the camstack 62. The delay drive blade 480 is used on cam-operated
timers that are configured with the optional feature of delay drive 604. The
primary drive blade 476, secondary drive blade 478, and delay drive blade 480
are
about 0.046 of an inch (0.117 cm) wide. The delay drive blade 480 is engaged
by
the camstack drive 64 to rotate the camstack 62 at a slower speed than when
the
camstack drive 64 engages the primary drive blade 476 and secondary drive
blade
478. The drive teeth 482 are located on the primary drive blade 476, secondary
26
CA 02207543 1997-OS-28
y
drive blade 478, and delay drive blade 480 at predetermined intervals to
provide
incremental frictional surfaces for the camstack drive 64 to engage the
camstack
for rotation about the control shaft axis. Drive teeth 482 spacing may vary on
the
drive blades 474 to alter the rotational speed of the camstack 62 in the range
from
about 4.5° to 7.5° of camstack rotation for each camstack drive
increment.
Predetermined portions of the delay drive blade 480 will not have drive teeth
482
when the same predetermined portions of the primary drive blade 476 has drive
teeth 482 and vice versa. The camstack drive 64 keeps synchronized by having
drive teeth 482 on either the delay drive blade 480 or primary drive but not
both.
The delay profile 488 is located on the camstack interior diameter opposite
the
hub extension 452. The delay profile 488 contains predetermined information to
engage and disengage a component of the camstack drive 64. In bi-directional
applications, the delay profile 488 is configured to operate in either
direction.
The detest blade 484 is engaged by the cycle selector detest 442 to
provide the operator with either tactile or auditory feedback or both from the
cycle
selector detest 442 to more easily select an appliance function when the shaft
control knob 504 is rotated. The detest blade 484 has a profile that can be
varied
to correspond with appliance cycles. With a uni-directional camstack, the
detest
blade 484 can be configured with build-up torque prior to selection of a cycle
and
with an even greater exit torque prior to moving from the selected cycle. With
a
bi-directional camstack, the detest blade 484 is typically configured with
about the
same build-up torque as exit torque from a selection, so an appliance operator
is
given similar feedback during each direction of camstack rotation. The
camstack
face 486 can also be engaged by the cycle selector detest 442 to provide the
operator with either tactile or auditory feedback or both from the cycle
selector
detest 442 to more easily select an appliance function when the shaft control
knob
504 is rotated.
The following camstack profile configuration description is only one example
of how camstack profiles 436 may be arranged. For reference purposes, the
camstack switch program blades 466, drive blades 474, and detest blade 484 are
numbered from zero through fourteen starting from the switch program blade
opposite the camstack hub extension. The switch program blades 466 are the
even numbered camstack blades (0, 2, 4 . . .14). The primary drive blade 476
is
camstack blade number one, the secondary drive blade 478 is camstack blade
27
CA 02207543 1997-OS-28
number three, the delay drive blade 480 is number five, and the detest blade
484
is number thirteen.
The control shaft 438 includes a shaft base end 492, a shaft bore 494 (see
FIG. 11 ), a shaft displacement stop 496, a shaft hub bearing 498, a shaft
control
end 500, a shaft locking pin 502, and a shaft control knob 504. The control
shaft
438 cooperates with the base control shaft mount 142, and camstack hub 434 to
provide a rotational axis for the camstack 62. The control shaft 438 is
axially
displaceable to a first depressed position and a second extended position. The
control shaft control knob 504 is used by an appliance operator to select an
appliance cycle and operate the master switch to turn the appliance 50 "on"
and
"off'. The control knob 504 is also used by an appliance operator to actuate
the
optional quiet cycle selector . The control shaft 438, with the exception of
the
shaft locking pin 502 and shaft control knob 504, is preferably manufactured
from
a rigid plastic such as G.F Nylon. The control shaft 438 is an option used on
cam-operated timers with a master switch. If a control shaft 438 is not used
in a
cam-operated timer configuration, such as a dishwasher, the clutch 440 is also
eliminated, and the camstack hub 434 is modified to cooperate with the base
control shaft mount 142 to provide a bearing for rotation of the camstack 62.
Also
when a control shaft 438 is not used the shaft control knob 504 is coupled to
the
hub extension 452 by the hub extension grooves 454.
The shaft base end 492 includes a shaft base end assembly detail 506 (see
FIG. 11), a shaft circular ramp 508, shaft base bearings 510, and shaft twist
lock
ribs 512. The base end assembly detail 506 provides frictional surfaces for a
manual or automated tool to rotate the control shaft 438 during assembly. The
shaft circular ramp 508 includes a shaft lift ramp 514, a shaft retention
latch 516,
and a shaft lift bearing 518. The shaft circular ramp 508 is used to by an
appliance operator to actuate the master switch and quiet cycle selector . The
shaft lift ramp 514 cooperates with the master switch and quiet cycle selector
to
convert axial displacement of the control shaft 438 to right angle
displacement of
master switch and quiet cycle selector components operating parallel to the
base
platform 84. The lift ramp is formed at about a 45° angle and has a
height of
about 0.140 of an inch (0.356 cm). The outer diameter of the lift ramp is
about
0.790 of an inch (2.007 cm).
The shaft retention latch 516 cooperates with master switch and quiet cycle
28
CA 02207543 1997-OS-28
' ~
t
selector components to temporarily lock the master switch in the actuated
"off'
position and, if so equipped, temporarily lock the quiet cycle selector in the
actuated "select" position. The retention latch 516 is also ramp shaped and
forms
about a 150° angle which is also about a 30° reverse angle in
relation to the shaft
lift ramp 514. The shaft lift bearing 518 cooperates with master switch and
quiet
cycle selector components to provide a bearing for rotation between the
control
shaft 438 and the master switch when in the actuated "off' position and quiet
cycle
selector when in the actuated "select" position. The shaft lift bearing 518 is
about
0.010 of an inch (0.025 cm) wide flat surface parallel to the axial length of
the
control shaft 438.
The shaft base bearings 510 include a shaft base end bearing 522, a shaft
base internal bearing 524, a shaft base clutch bearing 526, and a shaft base
clutch bearing ledge 528. The shaft base end bearing 522 cooperates with
housing base 74 to provide a thrust bearing and indexing stop for the control
shaft
438 when the control shaft 438 is indexed in toward the housing base 74. The
shaft base internal bearing 524 cooperates with the housing base control shaft
mount 142 to locate the control shaft in the housing base 74 and to provide a
bearing for rotation of the control shaft 438. The shaft base clutch bearing
526
cooperates with the clutch 440 to provide a stable, low-friction bearing for
rotation
of the camstack 62 on the control shaft 438. The shaft base clutch bearing
ledge
528 retains a clutch component during assembly of the control shaft 438 and
clutch 440 to the camstack 62.
The shaft twist lock ribs 512 include shaft rib ends 530, a shaft rib
interruption 532, and a shaft rib base edge 534. The twist-lock ribs 512
provide a
structure to attach a clutch component to the control shaft 438. The twist-
lock ribs
512 are about 0.045 of an inch (0.114 cm) wide and the rib interruption 532 is
about 0.060 of an inch (0.152 cm) wide. The distance between the shaft rib
base
edge 534 and the shaft base clutch bearing 526 is about 0.070 of an inch
(0.178
cm). The shaft rib ends 530 are chambered at about 45° for easier
installation of
a clutch component. The shaft bore 494 extends through the entire length of
the
control shaft 438 and provides space for the shaft locking pin 502.
The shaft displacement stop 496 cooperates with the camstack hub
displacement stop 462 to control the distance the control shaft 438 can be
indexed
out, moved to an extended position, by an appliance operator to place the
master
29
CA 02207543 1997-OS-28
switch in the unactuated "on" position and the quiet cycle selector in the
unactuated "operate" position. The displacement stop 496 provides a positive
stop
for the control shaft 438 at one of the strongest points in the camstack hub
434.
The displacement stop prevents the control shaft base end 492 from contacting
the clutch disk 560 to control displacement. The shaft hub bearing 498
cooperates with the camstack hub inner bearing 460 to provide a bearing for
rotation of the camstack 62 around the control shaft 438 when the camstack 62
is
driven for rotation by the camstack drive 64.
The shaft control end 500 includes shaft spring arms 536, shaft spring arm
barbs 538, shaft spring arm ribs 540, and a shaft control end stop 542. The
shaft
control end 500 typically extends through an appliance control console and
provides structure to attach the control knob 504 onto the control shaft 438.
The
shaft spring arms 536 are rectangular in shape with a taper and located about
180° apart on the shaft control end 500. The spring arms 536 extend
about 0.415
of an inch (1.054 cm) from the shaft control end stop 542. When a control knob
is
placed over the two spring arms 536 it boxes in the two spring arms to permit
both
clockwise and counter-clockwise rotation of the control knob by an operator.
The
shaft spring arm barbs 538 extend from the shaft spring arm ends to provide a
structure to lock the control knob on the control shaft 438 to prevent the
control
knob from being pulled off the control shaft 438 when an appliance operator
indexes the control shaft 438 out away from the appliance console. The control
shaft end stop 542 provides a stable seat from the control knob on the control
shaft 438 and the shaft end stop 542 also limits movement of the control knob
toward the shaft base end 492.
The shaft locking pin 502 includes a shaft locking pin knob groove 544, a
shaft locking pin stop 546, a shaft locking pin retention spring 548, and a
shaft
locking pin base end 550. The shaft locking pin 502 is inserted through the
base
hub opening 144 and into the camstack hub bore 458 to lock the control knob
504
onto the control shaft 438. The shaft locking pin knob groove 544 is designed
to
receive shaft spring arm ribs 540 to secure the shaft locking pin 502 in
position.
The shaft locking pin stop 546 extends from the shaft locking pin 502 to
interfere
with shaft bore 494 to limit movement of the shaft locking pin 502 toward the
shaft
control end 500. The shaft locking pin retention spring 548 also interferes
with the
housing base control shaft mount 142 to restrict movement of the shaft locking
pin
CA 02207543 1997-OS-28
out of the shaft base end 492 prior to the control knob being installed on the
shaft
control end 500. The shaft locking pin base end 550 is a flattened surface
that
can be used as an assembly aid in automated or manual insertion of the shaft
locking pin 502 in the shaft bore 494. The shaft locking pin base end 550 also
permits gripping the shaft locking pin 502 for manual removal of the shaft
locking
pin 502 and control knob if the cam-operated timer 52 is removed from an
appliance console.
The shaft control knob 504 includes shaft knob spring arm slot 552, shaft
knob barb seats 554, and a shaft knob stop (hidden from view). The shaft knob
spring arm slot 552 receives the shaft spring arms 536 to permit the control
knob
to rotate the control shaft 438 bi-directionally The shaft knob barb seats 554
receive the shaft spring arm barbs 538 to prevent the control knob from being
pulled ofF when the control shaft 438 is indexed out away from the base
platform
84. The shaft knob stop cooperates with the shaft control end stop 542 to
prevent
the knob 504 from sliding down the control shaft 438 when the control shaft
438 is
indexed in toward the base platform 84. When the shaft locking pin 502 is
installed the shaft spring arms 536 are prevented from flexing inward to
maintain
the shaft spring arm barbs 538 engaged with the shaft knob barb seats 554.
The clutch 440 includes a ratchet 558 and a clutch disk 560. The clutch
couples the control shaft 438 to the camstack 62 when the control shaft 438 is
indexed inwardly toward the base platform 84 to allow an appliance operator to
select an appliance cycle. The clutch 440 decouples the control shaft 438 from
the camstack 62 when the control shaft is indexed outwardly away from the base
platform 84, so the appliance operator cannot rotate the camstack while the
camstack 62 is operating the blade switches. The clutch 440 can be configured
to
permit bi-directional or uni-directional rotation of the camstack when control
shaft
438 is indexed inwardly toward the base platform 84. When the clutch 440 is
assembled on the control shaft 438 and attached to the camstack 62 inside the
clutch cavity 446, the clutch 440 captures the control shaft 438 within the
camstack hub 434 to make assembly of the camstack 62 in the housing base
easier. The clutch 440 can be manufactured from a plastic such as acetal. The
clutch 440 is an option used on cam-operated timers with a control shaft 438.
The clutch ratchet 558 includes a ratchet base 562, a ratchet bore 564,
flexible fingers 566, a twist-lock latch 576, a twist lock stop 578, anti-
tangle
31
CA 02207543 1997-OS-28
t
projections 580, and a ratchet assembly pin 582. The ratchet base 562 provides
a
stable platform to carry clutch ratchet components and defines the ratchet
bore
564. The ratchet bore 564 is sized to permit the ratchet 558 to be installed
over
the control shaft control, end 500 and locate on the shaft base clutch bearing
ledge
528. The flexible fingers 566 include first direction ratchet springs 568,
second
direction ratchet springs 570, first direction ratchet teeth 572, and second
direction
ratchet teeth 574. The first direction ratchet springs 568 and second
direction
ratchet springs 570 are cantilever springs that extend from the ratchet base
562.
The first direction ratchet springs 568 and second direction ratchet springs
570
can flex to ease engagement of the ratchet 558 with the clutch disk 560 and
can
flex to permit the ratchet 558 to disengage from the clutch disk 560. The
first
direction ratchet teeth 572 are carried on the first direction ratchet spring
568 and
the second direction ratchet teeth 574 are carried on the second direction
ratchet
spring 570. Both the first direction ratchet teeth 572 and second direction
ratchet
teeth 574 are camped shaped to facilitate engagement and disengagement from
the clutch disk 560.
The twist-lock latch 576 and twist-lock stop 578 cooperate with the control
shaft twist lock ribs 512 to secure the ratchet 558 onto the control shaft
438.
More specifically the twist-lock latch 576 engages the shaft rib interruption
532
and the twist-lock stop 578 engages the shaft rib edge 534 to secure the
ratchet
base 562 on the shaft base clutch bearing ledge 528. The twist-lock latch 576
is a
cantilever spring that compresses when rotated to engage the control shaft
twist
lock ribs 512 and expands when the twist-lock latch 576 engages a shaft rib
interruption 532. The twist-lock latch 576 has a camped surface at about
45° that
extends from the ratchet base 562 about 0.025 of an inch (0.064 cm). The anti-
tangle projections 580 extend from the ratchet base 562 near the first
direction
ratchet teeth 572 and second direction ratchet teeth 574 to reduce the
opportunity
for more than one ratchet 558, for instance in a vibratory feeder bowl (not
shown),
to become tangled together and interfere with assembly. The ratchet assembly
pin 582 is asymmetric to the ratchet 558 and extends from the ratchet base 562
to
facilitate use of automated assembly equipment such as vibratory feeder bowls
and pick-and-place machines (not shown).
The ratchet springs 568, 570 can be either unidirectional ratchet springs or
bi-directional ratchet springs. The unidirectional ratchet springs include
first
32
CA 02207543 1997-OS-28
w
direction ratchet teeth 572. The bi-directional ratchet springs include both
first
direction ratchet teeth 572 and second direction ratchet teeth 574. When the
control shaft 438 is rotated in a direction to cause the clutch 440 to slip,
the
ratchet teeth disengage from the clutch 440 and then the ratchet teeth are
biased
to re-engage with the clutch 440. The first direction ratchet teeth 572 and
the
second direction ratchet teeth 574 are spaced so that all first direction
ratchet
teeth 572 and all second direction ratchet teeth 574 engage the clutch disk
560
simultaneously Both the unidirectional ratchet teeth and the bi-directional
ratchet
teeth have ratchet ramps of about a 45° ramp that extends from the
surface of the
clutch ratchet 558 about 0.048 of an inch (0.122 cm). With unidirectional
ratchet
teeth, rotation toward the ratchet ramps causes slippage.
The clutch disk 560 has a clutch control shaft bore 584, a clutch control
shaft bearing 586, clutch slots 588, clutch mounting notches 590, and clutch
assembly pins 592. The clutch disk 560 cooperates with the clutch ratchet 558
to
engage or disengage the control shaft 438 from the camstack. The clutch disk
560 also provides a bearing for the camstack hub 434 to rotate on the control
shaft 438. The clutch control shaft bore 584 is about 0.574 of an inch in
diameter
(1.458 cm) and has a 45° chamber for a depth of about 0.030 of an inch
(0.076
cm) and is sized to slide the control shaft 438 through the clutch shaft bore
584
and stop on the circular ramp ledge 520. The clutch control shaft bearing 586
cooperates with the control shaft base external bearing to provide for
rotation of
the camstack hub 434 on the control shaft 438.
The clutch slots 588 are spaced so that when an operator indexes the
control shaft 438 to select an appliance function the clutch ratchet teeth
engage
the clutch slots 588 to permit rotation of the camstack 62. The clutch slots
588
are sized larger than the clutch ratchet teeth for less interference when the
clutch
ratchet teeth engage the clutch slots 588. The clutch slots 588 have an outer
diameter of about 1.000 inch (2.540 cm) and an inner diameter of about 0.750
of
an inch (1.905 cm). Clutch slots 588 are positioned at about 12°
intervals around
the clutch disk 560. The clutch disk assembly pins 592 are an assembly aid
that
permits a clutch disk 560 to be aligned in a vibratory feeder bowl and track
assembly. The mounting notches 590 engage the clutch cavity clutch fasteners
450 to prevent the clutch disk 560 from rotating independently of the camstack
62.
The clutch disk 560 rests on the camstack clutch shelf 448 and two or more of
the
33
CA 02207543 1997-OS-28
clutch fasteners 450 are heat staked to secure the clutch disk 560 to the
camstack
hub 434.
The camstack 62 is assembled as follows. First, the clutch disk 560 is
fitted over the control shaft 438 and is retained by the control shaft. Second
the
clutch ratchet 558 is also fitted over the control shaft 438 and is attached
to the
control shaft with a twist-lock fitting. The control shaft base end details
506 can
be used by automated equipment to rotate the control shaft 438 to install the
clutch ratchet 558. Once the ratchet 558 is attached to the control shaft 438,
the
clutch disk 560 is captured on the control shaft. Third, the control shaft
with
retained clutch disk 560 and attached ratchet 558 are installed in the
camstack 62.
During installation of the clutch disk 560 into the camstack 62, the clutch
disk
mounting notches 590 align with clutch features 450 to seat the clutch disk
560
into the camstack 62. Two or more of the clutch features 450 are heat staked
to
secure the clutch disk 560 in the camstack. When the camstack 62 is seated on
the control shaft mount 142, the base camstack supports 146 contact the clutch
disk 560 to position the camstack 62 about 0.100 of an inch (0.254 cm) above
the
base platform 84 to prevent the camstack 62 from intertering with timer
components. The camstack 62 is assembled before installation into the housing
base 74 by assembling camstack components on a straight axis that is parallel
to
the camstack hub 434 using automated assembly equipment which is discussed in
a later section entitled "Assembly Of The Cam-Operated Timer".
The cycle selector detent 442 is an option for the cam-operated timer 52
that provides a tactile feel to the appliance operated during cycle selection.
The
cycle selector detent 442 includes a detent follower 598 and detent spring
596.
The detent follower 598 engages the detent blade 484 (see FIG. 106) to
transmit
tactile feel to the appliance operator during cycle selection. The detent
spring 596
biases the detent follower 598 toward the camstack detent blade 484. The cycle
selector detent 442 is carried in the first side cover detent follower channel
198
with the first side cover detent spring pilot 202 engaging the detent spring
596,
and the detent follower 598 extending through the detent follower bore 200 to
engage the camstack detent blade 484. The cycle selector detent 442 is
installed
on a vertical axis into the first side cover detent follower channel 198 as
one of
the last timer components installed typically after the blade switches 66 have
been
installed. The cycle selector detent 442 engages the camstack detent blade 484
34
CA 02207543 1997-OS-28
that has a profile that can be varied to correspond with appliance cycle. The
detent follower 598 can be configured for unidirectional operation or bi-
directional
operation. When an operator rotates the control shaft 438 to select an
appliance
function, the operator receives either tactile or auditory feedback or both
from the
cam-operated timer 52, so the operator can more easily select an appliance
function.
The camstack 62 can be configured without a control shaft 438 and clutch
440. In that case, the hub extension 452 includes a hub control dial
positioned
configured to carry a control knob 504. In this configuration the clutch
cavity 446
is eliminated and a hub base bearing formed to engage the base control shaft
mount 142 to provide an axis for rotation of the camstack 62. In cam-operated
timer configurations without the optional master switch, the camstack profiles
436
can be configured to break all electrical contacts 744 of the blade switches
66 to
turn "off' an appliance 50 such as a dishwasher.
CAMSTACK DRIVE
Referring to FIGs. 2, 6, 7, 8 and 9, the camstack drive 64 includes a main
drive 602 and a delay drive 604. The main drive 602 includes a drive cam 606,
a
primary drive pawl 608, a secondary drive pawl 610, and a drive spring 612.
The
motor transmits torque through the output gear 396 to the drive cam 606 which
in
turn operates the primary drive pawl 608 and secondary drive pawl 610 to
rotate
the camstack 62. The drive cam 606, primary drive pawl 608, and secondary
drive pawl 610 are preferably manufactured from a rigid plastic with good wear
characteristics such as glass-filled nylon. Assembly of the camstack drive 64
is
described in a subsequent section titled "Assembly Of The Carn-Operated
Timer".
The drive cam 606 (see FIGs. 12a, 12b, and 12c) includes a drive cam
base 614, a subinterval cam 616, a separation shelf 618, a drive engagement
cam
620, a drive lug 622, a delay drive lug 624, a delay drive bearing 626, a
secondary
drive cam 628, and a drive cam top 630. The drive cam 606 is carried for
rotation
on the base drive cam mount 102 and driven for rotation by the output gear 396
connected to the drive cam top 630. The drive cam 606 operates the camstack
main drive 602 as the primary means to drive the camstack for rotation, and
the
delay drive 604 as a secondary means to drive the camstack for rotation when
slower rotation of the camstack is desired. The drive cam 606 through the
CA 02207543 1997-OS-28
.S
9
subinterval cam 616 also operates the subinterval switch to operate at least
one
blade switch 66 independent of the camstack 62.
The drive cam base 614 includes a drive base bearing 632, a drive interior
key 634, and a drive thrust bearing 636. The drive base bearing 632 fits into
the
base drive cam mount 102 to provide for rotation of the drive cam 606. The
drive
base bearing 632 has a drive interior key 634 to permit alignment of the drive
cam
606 during installation. An additional feature of the drive interior key 634
is to
permit a service person to determine if the drive cam 606 is rotating since an
operating timer may be so quiet that it could be difficult to determine if the
motor is
operating the drive cam 606. The drive thrust bearing 636 engages the side of
the
drive cam mount 102 nearest the first open side 80 to axially align the drive
cam
606.
The subinterval cam 616 is engaged by the subinterval switch to operate at
least one blade switch 66 independently of the camstack 62. The separation
shelf
618 assists in capturing the subinterval switch in the housing base 74. The
subinterval cam 616 is sequenced with the drive stroke to engage and disengage
a switch from the camstack 62 unless masked.
The primary drive engagement cam 620 functions to control engagement of
the drive lug 622 of the primary drive pawl 608 with the drive lug track 640.
The
drive lug 622 cooperates with the drive lug track 640 to translate the drive
cam's
rotary motion to substantially linear motion of the primary drive pawl 608.
The
primary drive engagement cam 620 engages the engagement track 638 of the
secondary drive pawl 608 and functions to disengage the drive lug 622 from the
drive lug track 640 during predetermined periods. The drive lug 622 is hook
shaped and engages the drive lug track 640 to convert the rotary movement of
the
drive lug 622 to a lift and linear pulling motion of the primary drive pawl
608. The
delay drive lug 624, also know as a delay drive cam, cooperates with the delay
drive 604 to convert the drive cam's rotary motion to a substantially linear
motion
to operate the delay drive 604.
The secondary drive cam 628 engages the secondary drive track 654 of the
secondary drive pawl 610 to convert the rotary movement of the secondary drive
cam 628 into a substantially linear motion. The secondary drive pawl 610
engages the camstack secondary drive blade 478 to prevent the primary drive
pawl 608 from reversing camstack rotation during the primary drive pawl's
return
36
CA 02207543 1997-OS-28
a
x
stroke. The secondary drive pawl 610 is imparted with about a 0.006 inch
(0.015
cm) linear tangential pulling motion that advances the camstack 62 slightly
during
the primary drive pawl's return stroke to improve the primary drive pawl's
engagement of the primary drive blade 476 at the end of the primary drive
pawl's
return stroke.
The drive cam top 630 includes a disconnect drive bearing 631, drive
splines 633, and drive spline tips 635. The drive disconnect bearing 631 is a
sleeve bearing that cooperates with the output gear disconnect bearing 404 to
disconnect the drive cam 606 from the output gear 396 during cam-operated
timer
testing before the spline connector 334 is installed. The drive splines 633
are
engaged by spline connector 334 to couple the drive cam 606 to the output gear
396. The drive spline tips 635 are tapered at about a 45° on each side
of the
splines to a point to permit easier installation of the spline connector 334.
By
having both the drive cam spline tips 635 tapered and the internal connector
spline tips 422 tapered, flat surtaces are eliminated that could butt against
one
another to complicate installation. Once the spline connector 334 is
installed, the
drive splines 633 are locked with the output gear splines 412 to connect the
output
gear 396 to the drive cam 606 for operation of the cam-operated timer 52.
The primary drive pawl 608 (see FIGs. 13a, 13b 13c) has an engagement
track 638, a drive lug track 640, a first drive tip retainer 642, a second
drive tip
retainer 644, a primary drive tip 646, a drive foot 648, and a torsion spring
shelf
650. The engagement track 638 cooperates with the drive engagement cam 620
to control engagement of the drive lug 622 with the drive lug track 640. The
drive
lug track 640 cooperates with the drive lug 622 to translate the drive cam's
rotary
motion into linear movement of the primary drive pawl 608. The primary drive
tip
646 engages the camstack primary drive blade 476 at predetermined intervals
with
a tangential pulling movement to rotate the camstack 62. Using a pulling
motion
reduces flexing of the primary drive pawl 608 which reduces the opportunity
for the
primary drive pawl 608 to cam-out by losing engagement with the primary drive
blade 476. Camstack advance can be varied from about 4.5° to
7.5° of camstack
rotation depending upon drive blade teeth 482 spacing. The first drive tip
retainer
642 and second drive tip retainer 644 extend below the primary drive tip 646
and
selectively engage the primary drive blade 476 to assist in keeping the
primary
drive pawl 608 in proper alignment with the camstack 62 during operation and
37
CA 02207543 1997-OS-28
'~
1 i
during functioning of the quiet cycle selector . The primary drive foot 648 is
used
to properly position the primary drive pawl 608 during assembly and to provide
means for retracting the primary drive pawl 608 for quiet cycle selection.
The secondary drive pawl 610 (see FIGs. 14a, 14b, 14c, 14d) has spacing
legs 652, a secondary drive track 654, a third drive tip retainer 656, a
fourth drive
tip retainer 658, a secondary drive tip 660, a secondary drive foot 662, and a
drive
spring contactor 664. The spacing legs 652 ride on the primary drive pawl 608
to
properly position the secondary drive pawl 610. The secondary drive track 654
has about a 0.003 of an inch (0.008 cm) offset eccentric. The secondary drive
tip
660 engages the secondary drive blade 478 with a tangential pulling movement
to
prevent the primary drive pawl 608 from reverse rotating the camstack during
the
primary drive pawl's return stroke and to slightly rotate the camstack 62
during the
primary drive pawl's return stroke. Using a pulling motion reduces flexing of
the
secondary drive pawl 610 which reduces the possibility that the secondary
drive
pawl 610 will cam-out by losing engagement with the secondary drive blade 478.
The third drive tip retainer 656 and the fourth drive tip retainer 658
function to
keep the secondary drive pawl 610 properly aligned on the secondary drive
blade
478. The secondary drive foot 662 assists in aligning the secondary drive pawl
610 during installation and also permits retraction of the secondary drive
pawl 610
by the quiet cycle selector . The drive spring contactor 664 off sets the
drive
spring 612 to reduce interference between the drive spring 612 and the primary
drive pawl 608.
The drive spring 612 (see FIG. 35a) is a torsion spring and has a coil 666,
a first spring end 668, and a second spring end 670. The drive spring 612 is
installed after the camstack 62 has been installed on the drive spring mount
base
detail 108 with the first spring end 668 contacting the primary drive pawl
spring
ledge 650 and the second spring end 670 contacting the secondary drive pawl
foot
662. The drive spring 612 provides about a 0.200 pound (0.090 Kg) biasing
force
to the primary drive pawl 608 and the secondary drive pawl 610. The drive
spring
612 is a coil spring rather than a leaf spring because a coil spring has
advantages
including providing a more constant force and each end of the coil spring can
perform a biasing function.
The delay drive 604 includes a delay drive wheel 672, a delay camstack
pawl 674, a delay ratchet pawl 676, a delay no-back pawl 678, and a masking
38
CA 02207543 1997-OS-28
lever 680. The delay drive 604 is a second optional pawl drive system that is
programmed to operate at predetermined intervals in lieu of the camstack drive
64
to greatly reduce regular camstack rotational speed, in the range of 1,500 to
2,200
percent, for functions such as in-cycle delay and delay-to-start. By reducing
camstack rotational speed during delay functions, switch program blade space
can
be conserved. The delay drive 604 is activated and inactivated by the masking
lever 680 according to a predetermined program carried on the camstack delay
profile 488. The delay drive 604 is synchronized with the camstack drive 64 so
when the delay drive 604 is activated the angular location of the delay
ratchet
pawl 676 is known to permit more precise control of the delay drive 604 in
relation
to the camstack drive 64. The delay drive could also be accomplished with
reduction gears.
The delay drive wheel 672 (see FIGs. 30a, 30b, 31) has a delay wheel bore
682, a delay ratchet 684, a delay pawl tip retainer 686, a delay cam bearing
687,
and a delay drive lug 688. The delay drive wheel bore 682 has a delay wheel
first
bearing 683, and a delay wheel second bearing 685. When the delay drive wheel
bore 682 is installed on the housing base delay wheel mount 122, the delay
wheel
first bearing 683 and the delay wheel second bearing 685 cooperate with the
housing base delay wheel mount 122 to provide for more stabilized rotation
than
can typically be provided with a single bearing surface. The delay ratchet 684
is
engaged by the delay ratchet pawl 676 and delay no-back pawl 678 to
incrementally rotate the delay drive wheel 672. The delay pawl tip retainer
686 is
a shelf to prevent the delay ratchet pawl 676 and delay no-back pawl 678 from
moving out of alignment with the ratchet 684 toward the first side cover 76.
The
delay cam bearing 687 engages the delay camstack pawl 674 to properly align
the
delay camstack pawl 674 in relation to the delay drive lug 688. The delay
drive
lug 688 engages the delay camstack pawl 674 to reciprocate the delay camstack
pawl 674 in predetermined fashion to engage the camstack delay drive blade
480.
The delay camstack pawl 674 (see FIGs. 27a, 27b) has a delay camstack
pawl alignment track 690, a delay camstack pawl lug track 692, a delay
camstack
pawl tip 694, a delay camstack pawl tip retainer 696, a delay camstack pawl
spring post 698, a delay camstack pawl foot 700, delay camstack pawl supports
702, and a delay camstack pawl spring 704. The delay camstack pawl 674 is
operated by the delay wheel 672 to engage the camstack delay blade 480 to
drive
39
CA 02207543 1997-OS-28
the camstack for rotation during predetermined periods of delay During quiet
cycle selection, the delay camstack pawl 674 is engaged by quiet cycle
selector
components to disengage the delay camstack pawl 674 from the camstack delay
blade 480 to reduce noise generated by the delay camstack pawl 674 when the
camstack 62 is manually rotated.
The delay camstack pawl alignment track 690 engages the delay cam
bearing 687 to properly align the delay camstack pawl lug track 692 in
relation to
the delay drive lug 688. The delay camstack pawl lug track 692 is engaged by
the
delay drive lug 688 to convert the delay drive wheel rotary motion to a
substantially linear motion of the delay camstack drive pawl 674. The delay
drive
lug 688 cooperates with the delay camstack pawl lug track 692 to drive the
camstack 62 during about 90° of delay wheel rotation and retract the
delay
camstack pawl 674 during about 90° of rotation. Preceding both the
advance and
retraction there is a 90° dwell. When the camstack delay operates to
drive the
camstack 62 for rotation, the secondary drive pawl 610 continues to operate to
prevent the camstack 62 from reverse rotation during the time period when the
camstack delay drive 604 is operating.
The delay camstack pawl tip 694 engages the camstack delay blade 480 to
drive the camstack 62 for rotation at predetermined intervals. The delay
camstack
pawl tip retainers 696 assist in maintaining proper delay camstack pawl tip
694
alignment in relation to the camstack delay blade 480. The delay camstack pawl
spring post 698 provides a means for attaching the delay camstack pawl spring
704 between the delay camstack pawl 674 and the motor pedestal 134 to bias the
delay camstack drive pawl 674 toward the camstack 62 for contact with the
delay
drive blade 480. The delay camstack pawl spring 704 is an extension spring
with
delay camstack pawl spring loops 706 that are installed with the delay
camstack
pawl spring loops 706 oriented toward the housing base platform 84. One of the
delay camstack pawl spring loops 706 is connected to the motor pedestal 134
and
located by motor pedestal ribs 136 and the other delay camstack pawl spring
loop
706 is connected to the delay camstack pawl spring post 698 to bias the delay
camstack pawl 674 toward the camstack delay drive blade 480.
The delay camstack pawl foot 700 is used as a contact point with quiet
cycle selector components to lift the delay camstack pawl 674 away from the
camstack delay drive blade 480. The delay camstack pawl supports 702 contact
CA 02207543 1997-OS-28
v
the motor stator cup 256 to serve as a thrust bearing to maintain the delay
camstack pawl 674 in proper alignment with the delay wheel 672 and to capture
both the delay camstack pawl 674 and delay wheel 672 in the housing base 74
once the motor is installed.
The delay ratchet pawl 676 (see FIG. 28) has a delay ratchet pawl track
708, delay ratchet pawl track extensions 710, a delay ratchet pawl tip 712, a
delay
ratchet pawl tip retainer 714, a delay ratchet pawl foot 716, and a delay
ratchet
pawl spring post 718. The delay ratchet pawl 676 is driven by the drive cam
606
to engage the delay wheel ratchet 684 to rotate the delay wheel 672. The delay
ratchet pawl track 708 engages the drive cam delay drive lug 624 to convert
the
drive cam rotary motion to reciprocate the delay ratchet pawl 676 for
engagement
with the delay wheel ratchet 684. The delay ratchet pawl tip 712 engages the
delay ratchet 684 to incrementally rotate the delay drive wheel 672. The delay
ratchet pawl tip retainer 714 cooperates between the delay wheel bearing 687
and
the delay drive wheel 672 to prevent the delay ratchet pawl 676 from moving
toward the first open side 80 and out of alignment with delay ratchet 684. The
delay ratchet pawl foot 716 cooperates with the housing base platform 84 to
prevent the delay ratchet pawl 676 from moving toward the housing base
platform
84 and out of alignment with the delay ratchet 684. The delay ratchet pawl
foot
716 also is contacted by the masking lever 680 to move the delay ratchet pawl
676 away from the delay ratchet 684 during predetermined periods when the
delay
drive 604 is to be inactivated. The delay ratchet pawl spring 720 (see FIG.
35c) is
an extension spring that has one end connected to the delay ratchet pawl
spring
post 718 and its other end connected to the base delay spring support post 116
to
bias the delay ratchet pawl tip 712 toward the delay ratchet 684.
The delay no-back pawl 678 (see FIG. 29) has a delay no-back pivot 724, a
delay no-back tip 726, a delay no-back spring post 728, and a delay no-back
spring 730. The delay no-back pawl 678 functions to prevent the delay drive
wheel 672 from reversing rotation when driven by the delay ratchet pawl 676,
and
the delay no-back pawl 678 functions to keep the delay drive wheel 672
stationary
when the delay ratchet pawl 676 is lifted away from the delay ratchet 684 when
the delay is inactivated. The delay no-back pivot 724 is carried on the drive
cam
delay drive bearing 626. The delay no-back tip 726 engages the delay ratchet
684. The delay no-back spring 730 is a compression spring with one end carried
41
CA 02207543 1997-OS-28
G
on delay no-back spring post 728 and the other end carried on the base delay
no-
back spring seat 118 to bias the delay no-back pawl 678 toward the ratchet
wheel
684.
The delay masking lever 680 (see FIG. 32) has a masking pivot bore 732,
masking bearings 734, a masking follower 736, and a masking lifter 738. The
delay masking lever 680 operates in accordance with a predetermined program
encoded on the camstack delay profile 488 to activate and inactivate the delay
drive 604. The masking lever 680 is mounted in the housing base 74 by placing
the masking pivot bore 732 over the base masking lever pivot pin 114, and the
masking bearing 734 contacting the housing base platform 84 to reduce friction
when the masking lever 680 is operated. The masking follower 736 follows the
camstack delay profile 488 to move the masking fever 680 according to a
predetermined program. The masking lifter 738 contacts the delay ratchet pawl
foot 716 in response to the camstack delay profile 488 to move the delay
ratchet
pawl tip 712 away from the delay ratchet 684 to inactivate the delay drive
604. By
using the masking lever 680 to activate and inactivate the delay drive 604, a
portion of a delay increment can be selected that is typically in the range
from
95%-25% for a full delay increment.
BLADE SWITCHES
Deferring to FIG. 9, the blade switches include a terminal end 740, a
contact end 742, electrical contacts 744, lower contact wafer assembly 746,
cam
follower wafer assembly 748, upper contact wafer assembly 750, blade switch
terminals 752, motor terminal connectors 754, blade switch fasteners 756,
blade
switch bussing 758, an appliance motor start switch 760, and an appliance
motor
run switch 762. The blade switches 66 are carried by the second side cover 78
and are placed in working relationship to the camstack program blades 466 to
control appliance electrical circuits when the second side cover 78 is
attached to
the housing. The plastic molded components in the blade switches 66 are molded
from a plastic such as a PB.T polyester 15% G.l= / 20% M.F unless otherwise
noted. The terminal end 740 is fixed and carried by the housing. The contact
end
742 is moveable and carries the electrical contacts 744.
The lower contact wafer assembly 746 includes a lower contact wafer 764,
lower contact wafer bores 766, lower switch blades 768, lower blade electrical
42
CA 02207543 1997-OS-28
contacts 770, and blade spring supports 772. The lower contact wafer 764
provides a housing for the lower switch blades 768 and is a plastic such as a
PB.T polyester 15% G.F / 20% M.F The lower contact wafer bores 766 are
chambered to increase the target zone for rivets during assembly The lower
switch blades 768 are insert molded into the lower contact wafer 764 at about
a 0°
deflection angle. The lower switch blades 768 are manufactured from a metal
that
has good conductive and spring characteristics such as 260 cartridge brass.
The lower electrical contacts 770 are manufactured from a metal tape with
good conductive and wear characteristic such as from a silver-cad oxide alloy,
a
silver-cad oxide alloy cap on a copper alloy base, or a copper alloy The lower
electrical contacts 770 are attached to the lower switch blades 768 with a
micro-
resistance weld and then a light coining operation takes place to make the top
surface of the lower electrical contact 770 slightly convex to compensate for
tolerance variations in the angle of attack closure angle of the mating lower
blade
electrical contacts 770 and cam-follower lower electrical contacts 798. Lower
electrical contacts manufactured from metal tape require a much lighter
coining
operation than prior art cold headed or riveted contacts. Thus, lower
electrical
contacts 770 manufactured from metal tape result in less deformation of the
lower
switch blades 768 for better alignment and quality of the blade switches. The
lower electrical contacts 770 can be configured as a light duty contact that
can
switch loads up to about 1.0 Ampere, a medium duty contact that can switch
loads
up to about 13.0 Amperes, or a heavy duty contact that can switch loads up to
about 15.0 Amperes.
The blade spring supports 772 include double cam-valley riders 774, a
single cam-valley rider 776, lower blade notches 778, a lower blade
subinterval
tab 780, lower blade supports 782, and lower blade arc barrier 784. The blade
spring supports 772 are insert molded onto each lower switch blade 768 and
functions to maintain proper alignment of the lower switch blades 768 in
relation to
the camstack 62. During insert molding of the blade spring supports 772, the
lower blade switch terminals are used to locate and attached the blade spring
supports 772 and the lower switch blades 768 have details that assist in
fixing the
blade spring supports 772 to the lower switch blades 768. The lower blade
support 782 in turn functions to maintain proper alignment of the lower switch
blades 768 in relation to the upper contact wafer assembly 750.
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CA 02207543 1997-OS-28
The double cam-valley riders 774 straddle program blades 466 contacting
camstack valleys 490 on both sides of a program blade 466. The single cam
valley rider 776 contacts on one camstack valley on one side of a program
blade
466. A single cam valley rider 776 is used on one of the endmost blade
switches
to reduce the overall width of the blade switches. A purpose of both the
double
and single cam valley riders 774, 776 is to maintain a constant distance
between
the lower contact blade 768 and the camstack 62. By maintaining a constant
distance between the lower switch blades 768 and the camstack the blade spring
supports 772 compensate for tolerance variations in the camstack and camstack
wobble. Both the double cam-valley riders 774 and single cam-valley riders 776
are about 0.032 of an inch (0.081 cm) wide. The program blade space within the
double cam-valley riders 774 is about 0.086 of an inch (0.217 cm). The lower
blade notch 778 provides clearance for the cam-follower wafer assembly 748 to
operate.
The lower blade subinterval tab 780 can be used with the optional
subinterval switch configured for single blade switch actuation. The lower
blade
subinterval tab 780 cooperates with the subinterval switch to maintain the
proper
alignment between the lower switch blade 768 and the subinterval switch. The
lower blade support 782 cooperates with the upper wafer assembly 750 to
maintain the correct separation between the upper wafer assembly 750 and the
cam-follower wafer assembly 748 and the lower wafer assembly 746. The lower
blade support 782 is about 0.035 of an inch (0.089 cm) wide. The lower blade
arc
barrier 784 reduces arcing that can occur between the blade switches. The
lower
blade arc barrier 784 permits the blade switches to be placed more closely
together than could be accomplished without a lower blade arc barrier 784.
The cam-follower wafer assembly 748 includes a cam-follower wafer 786,
cam-follower wafer bores 788, cam-follower switch blades 790, cam-follower
blade
top surface 792, cam-follower blade bottom surface 794, cam-follower blade
angle
forms 796, cam-follower lower electrical contacts 798, cam-follower upper
electrical contacts 800, cam-follower riders 802, cam-follower lift tabs 804,
cam-
follower extended lift tabs 806, cam-follower molding runners 808, and cam-
follower blade subinterval tab 810. The cam-follower wafer 786, cam-follower
wafer bores 788, cam-follower switch blades 790, cam-follower lower electrical
contacts 798, and cam-follower upper electrical contacts 800 are manufactured
44
CA 02207543 1997-OS-28
,
from materials and to standards similar to their corresponding components in
the
lower wafer assembly 746 described above with the following exceptions.
The cam-follower switch blades 790 are insert molded in the cam-follower
wafer 786 with a cam-follower blade angle form 796 of about 8.5°. The
cam-
follower blade angle form 796 is positioned about 0.022 of an inch (0.056 cm)
inside the cam-follower wafer 786 as measured from the cam-follower wafer edge
nearest the cam-follower riders 802. The cam-follower blade angle form 796
could
be positioned any distance inside the cam-follower wafer 786 and still achieve
the
advantage of encapsulating the cam-follower angle form. One advantage of
having the cam-follower angle form 796 located between the blade switch
terminals 752 and the cam-follower wafer edge nearest the cam-follower riders
802 is that force at the cam-follower lower electrical contacts 798 and cam-
follower upper electrical contacts 800 is more predictable because the
moveable
portion of the cam-follower switch blade 790 does not contain an angle form.
Another advantage of having the cam-follower angle form encapsulated in the
cam-follower wafer 786 is that cam-follower switch blade spring flex is more
consistent. An angle form is created in the cam-follower switch blade 790 by
exceeding the elastic limits of the cam-follower switch blade 790 to create a
permanent angle or angle form in the cam-follower switch blade 790. If the cam-
follower blade angle form 796 is placed on the moveable portion of the cam-
follower blade, material and manufacturing variances reduce the consistency of
cam-follower switch blade spring flex. Blade switch deflection is determined
where
y is deflection, W is load on beam, x is a point on the beam where deflection
is
being calculated, E is modulas of elasticity of material, I moment of inertia
of the
cross-section of the beam and p is beam length as expressed by the formula:
y E/ (3~-~
The cam-follower lower electrical contacts 798 and cam-follower upper
electrical contacts 800 are attached to the cam-follower blade 790 in a
similar
fashion and have similar advantages as the lower blade electrical contacts 770
described above with the following differences and advantages. The cam-
follower
contacts 798, 800 are attached to the cam follower blade 790 in a staggered
relation to the cam-follower blade top surface 792 and the cam-follower blade
CA 02207543 1997-OS-28
bottom surtace 794. More specifically the cam-follower upper contact 800 is
attached to the cam-follower blade top surface 792 between the cam-follower
rider
802 and the moveable contact end 742, and the cam-follower lower contact 798
is
attached to the cam-follower blade bottom surface 794 located between the cam-
follower rider 802 and the stationary terminal end 740. An advantage of
positioning the cam-follower upper contact 800 between the cam-follower rider
802
and the moveable contact end 742 is that a greater mechanical advantage is
provided to create faster more accurate switching and more contact movement
than when the cam-follower upper contact 800 is placed between the cam-
follower
rider 802 and the stationary terminal end 740. An additional advantage of
staggering the cam-follower lower electrical contact 798 and cam-follower
upper
electrical contacts 800 manufactured of metal tape with a light coining
operation to
manufacture the cam-follower lower electrical contacts 798 and cam-follower
upper electrical contacts 800 is that the cam-follower lower electrical
contact 798
and cam-follower upper electrical contact 800 can be different types rather
than
specifying both contacts to be the highest current rating of either the cam-
follower
lower electrical contact 798 or the cam-follower upper electrical contact 800.
For
instance the cam-follower lower electrical contact 798 could be a low current
contact and the cam-follower upper electrical contact 800 could be a high
current
contact rather than using both high current contacts to reduce cost. Also by
staggering the upper cam-follower contact 800 and the lower cam-follower
contact
798 on the cam-follower blade 790, electrical erosion of the cam-follower
blade
between the upper cam-follower contact and lower cam-follower contact is
reduced
because electrical arcing on the upper cam-follower contact 800 occurs at a
different location on the cam-follower blade 790 than arcing on the lower cam-
follower contact 798.
The cam-follower riders 802 are insert molded onto the cam-follower switch
blades 790 in a fashion similar to how the blade spring supports 772 are
insert
molded onto the lower switch blades 768 described above with the following
exception. The cam-follower molding runner 808 provides a path for plastic
during
insert two plate molding of the cam-follower riders 802, cam-follower lift
tabs 804,
and carn-follower extended lift tabs 806. The cam-follower riders 802 engage
the
switch program blades 466 to move the cam-follower switch blades 790 in
accordance with a predetermined program. The cam-follower lift surface is
46
CA 02207543 1997-OS-28
r
engaged by the master switch to lift the cam-follower blades 790 away from the
lower switch blades 768 to break electrical contact. The cam-follower extended
lift
tabs 806 extend about 0.040 of an inch (0.102 cm) from the cam-follower lift
surface and are engaged by the master switch in quiet cycle selector
configuration
to lift the cam-follower riders 802 high enough to clear the switch program
blades
top radius 468 to prevent noise from being generated by the cam-follower
riders
802 during quiet cycle selector operation in addition to breaking electrical
contact
with the lower switch blades 768. The cam-follower blade subinterval tab 810
extends about 0.040 of an inch (0.102 cm) from the edge the cam-follower
switch
blade 790 and is engaged by the subinterval switch to operate a blade switch.
The upper contact wafer assembly 750 includes an upper contact wafer
812, upper contact wafer bores 814, upper switch blades 816, upper blade angle
forms 818, upper electrical contacts 820, upper blade support tabs 822, upper
blade support notches 824, and upper switch blade extensions 826. The upper
switch blades 816, upper electrical contacts 820, and upper contact wafer 812
are
manufactured from materials and to standards similar to their corresponding
components in lower wafer assembly 746 described above. The upper switch
blades 816 are molded into the upper contact wafer 812 at an upper blade angle
form 818 of about 12° in a similar fashion to the cam-follower blade
angle forms
796 described above.
The upper blade support tabs 822 contact the lower contact spring supports
772 so the upper electrical contacts 820 will maintain a constant distance air
gap
from the lower electrical contacts 770. The upper wafer assembly component
contact the upper spring blade support about 0.180 of an inch (0.457 cm) above
the lower spring blade. The upper blade support tabs 822 are located between
the upper blade contact and the upper blade stationary end. A support notch
824
is formed in the upper blade 816 to permit clearance of an adjacent blade
switch
with an upper blade support tab 822. The upper switch blade extensions 826 are
engaged by the master switch or quiet cycle selector to lift the upper switch
blades 816 to break electrical contact with the cam-follower upper electrical
contacts 800.
The blade switch terminals 752 include blade switch alignment details 828
and blade switch terminal notches 830. The blade switch alignment details 828
can be blade switch bores that are used as an alignment detail during insert
47
CA 02207543 1997-OS-28
molding of the lower contact wafer assembly 746, the cam-follower wafer
assembly 748, and the upper contact wafer assembly 750. The blade switch
bores 828 are engaged by a wafer mold pin to increase molding accuracy of the
blade switches in the corresponding lower contact wafer 764, cam-follower
wafer
786, or upper contact wafer 812. The blade switch terminal notches 830 are an
assembly aid. An assembly fixture engages the blade switch terminal notches
830
during assembly of the blade switches to properly align the lower contact
wafer
assembly 746, the cam-follower wafer assembly 748, and the upper contact wafer
assembly 750 in relation to the blade switch terminals 752. By aligning the
lower
contact wafer assembly 746, the cam-follower wafer assembly 748, and the upper
contact wafer assembly 750 in reference to the blade switch terminals 752,
more
accurate blade switch alignment is achieved than alignment off a material such
as
a plastic molding. The terminals are integral to the switch blades and are
shaped
to meet National Electrical Manufacturers Association (NEMA) standards and to
accepted by a plug-type electrical connector.
The blade switch bussing 758 includes a horizontal bussing port 832, a first
vertical bussing port 834, a second vertical bussing port 836, bussing ridges
838,
bussing ridge motor connector slot 840, a bussing pins 842, and a bussing cap
844. Blade switch bussing 758 permits making permanent hard wire connections
between selected blade switch terminals 752 and provides a location for the
motor
terminal connectors 754 to bridge an electrical connection between the blade
switches and the motor terminals 262. The horizontal bussing port 832 allows
selected adjacent blade switch terminals 752 on the lower contact wafer
assembly
746 or cam-follower wafer assembly 748, or upper contact wafer assembly 750 to
be electrically connected. On selected adjacent blade switch terminals 752
where
an electrical connection is not desired, the material connecting the adjacent
blade
switch terminals 752 is lanced to break the electrical connection. The
horizontal
bussing port 832 provides adequate space so the material connecting the
adjacent
blade switch terminals 752 that is lanced remains connected to the blade
switches
to reduce manufacturing complications that can result from small loose pieces
of
blade switch material. The first vertical bussing port 834 provides an opening
to
insert bussing pins 842 to form electrical connections between lower switch
blades
768 and upper switch blades 816. The second vertical bussing port 836 provides
an opening to insert bussing pins 842 to form electrical connections between
cam-
48
CA 02207543 1997-OS-28
follower switch blades 790 and upper switch blades 816. The bussing ridges 838
form slots to carry bussing pins 842. The bussing ridge motor connector slot
840
receives a motor terminal connector component to align and secure the motor
terminal connector component in the lower contact wafer 764. The bussing pins
842 are used in the first vertical bussing port 834, the second vertical
bussing port
836, and on the blade switch terminals 752 to electrically connect selected
blade
switch terminals 752. The bussing cap 844 electrically insulates the bussing
pins
842 used on blade switch terminals 752 from an electrical connector (not
shown)
used on the blade switch terminals 752.
The motor terminal connectors 754 include a first motor connector 846, a
second motor connector 848, male motor connector guides 850, and a female
motor connector guide 852. The motor terminal connectors 754 cooperate with
the motor terminals 262 to electrically connect the blade switches to the
motor in a
fashion that permits automated assembly of the blade switches onto the housing
along a single axis. The first motor connector 846 includes a first motor
connector
shaft tip 854, a- first motor connector shaft 856, and a frst motor connector
clip
858. The first motor connector shaft tip 854 is chambered at about 45°
and offset
about 0.010 of an inch (0.0254 cm) toward the center of the first motor
connector
shaft 856 to guide both the first motor connector shaft tip 854 and first
motor
connector shaft 856 into the appropriate first vertical bussing port 834
during
assembly. The first motor connector shaft edges are bent to avoid having
opposing sharp edges that could cause jamming during assembly and to
strengthen the first motor connector shaft 856. The first motor connector
shaft
leading edges are chambered at about a 30° angle to further ease
insertion. The
first motor connector clip 858 is clothes pin shaped to create spring pressure
for a
good electrical connection with the motor terminal wire switch end 328. The
second motor connector 848 includes a second motor connector shaft tip 860, a
second motor connector shaft 862, a second motor connector clip 864, and a
second motor connector shaft extension 866. The second motor connector shaft
tip 860, second motor connector shaft 862 and second motor connector clip 864
are similar to those previously described for the corresponding components of
the
first motor connector 846. The second motor connector shaft extension 866
engages the bussing ridge motor connector slot 840 to assist in locating and
securing the second motor connector clip 864.
49
CA 02207543 1997-OS-28
t
The male motor connector guides 850 and female motor connector guide
852 are integral to the lower contact wafer 764 and engage the motor's center
motor terminal guide 322 and side motor terminal guides 324 (see FIG. 20a) to
align the motor terminal wire switch end with the first motor connector clip
858 and
the second motor connector clip 864 when the blade switches are installed on
the
housing.
The blade switch fasteners 756 include wafer rivets 242, male wafer
fasteners 868, and male wafer fastener ramps 870. The wafer rivets 242 are
installed through the lower contact wafer bores 766, the cam-follower wafer
bores
788, the upper contact wafer bore 814, and the second side cover wafer
mounting
bore 240 to secure the blade switches to the second side cover 78. The male
wafer fasteners 868 are formed by material from the lower contact wafer 764
and
the cam-follower contact wafer 786 and are engaged by the base female wafer
fastener 172 and cover female wafer fastener 226 to assist in securing the
blade
switches with attached second side cover 78 to the housing base 74 and first
side
cover 76. The male wafer fastener ramps 870 are chambered surfaces that
cooperate with the base female wafer ramp 174 and cover female wafer ramp 228
to increase the assembly target area and serve as a guide during installation
of
the blade switches with attached second side cover 78 onto the housing base 74
and first side cover.
The blade switches are assembled before installation into the housing base
74 by assembling blade switch components on a straight axis that is
perpendicular
to the blade switch terminals 752 using automated assembly equipment which is
discussed in a later section entitled "Assembly Of The Cam-Operated Timer".
The
upper wafer assembly 750 is stacked on top of the cam-follower wafer assembly
748 and the lower wafer assembly 746 is stacked under the cam-follower wafer
assembly 748. An assembly fixture assists in properly aligning the wafer
assemblies. Additionally, the second side cover notches help to properly place
the
upper contact wafer assembly 750 in relation to the second side cover 78.
Wafer
rivets 242 are installed through the stacked upper wafer assembly 750, cam-
follower wafer assembly 748, lower wafer assembly 746, and through the second
side cover 78. The rivets securely attach the blade switches to the second
side
cover 78.
The blade switch terminal notches 830 are used to align the lower contact
CA 02207543 1997-OS-28
Y
t
wafer assembly 746, the cam-follower wafer assembly 748, and the upper contact
wafer assembly 750 during installation in the second side cover 78. The mating
surfaces of the lower contact wafer assembly 746, cam-follower wafer assembly
748 and upper contact wafer assembly 750 are substantially smooth to permit
the
mating surface to align according to the blade switch terminal notches 830 to
more
accurately align lower switch blades 768 with the cam-follower switch blade
790
with the upper switch blades 816.
MASTER SlNITCH
Referring to FIG. 6, the master switch includes rocker lifter 872, a switch
lifter 874, a lifter spring 876, a rocker 878, and a lift bar 880. The master
circuit
switch 68 functions to lift cam-follower switch blades 790 and upper switch
blades
816 high enough to break electrical connections between the cam-follower
switch
blades 790, the lower switch blades 768, and the upper contact switch blades
816.
When all electrical connections are opened the appliance 50 is turned "off'.
The
master switch is an option used on cam-operated timers configured with a
control
shaft 438. In some configurations, the switch lifter 874 could directly lift
one or
more cam-follower switch blades 790 to eliminate the need for a rocker lifter
872,
rocker 878 and lift bar 880.
The rocker lifter 872 includes a rocker lifter pivot bore 882, a rocker lifter
notch 884, a rocker lifter spring connector 886, a rocker lifter ramp 888, a
rocker
lifter latch 890, and a rocker lifter contactor 892. The rocker lifter pivot
bore 882
engages the housing base rocker lifter pivot pin 150. The rocker lifter notch
884
provides clearance for the housing base rocker lifter retainer 152 during
installation of the rocker lifter 872. The rocker lifter spring connector 886
provides
a point of attachment for the lifter spring 876 to bias the rocker lifter ramp
888
toward the control shaft mount 142. The rocker lifter ramp 888 is angled at
45° to
complement the control shaft lift ramp 514 that is also 45°. The rocker
lifter latch
890 is a reverse ramp of 60° from the rocker lifter ramp 888 that
extends about
0.006 of an inch (0.0152 cm) from the rocker lifter 872 creating an overhang.
The
rocker lifter contactor 892 cooperates with the rocker 878 to impart motion to
the
rocker 878. The rocker lifter 872 is assembled into the housing base 74 by
aligning the rocker lifter pivot bore 882 with the rocker lifter pin 150 and
the rocker
lifter notch 884 with the rocker lifter retainer 152. Once the alignment is
complete
51
CA 02207543 1997-OS-28
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the rocker lifter 872 will simply drop into the housing base 74 on a axis
perpendicular to the base. The rocker lifter 872 operates when the control
shaft
438 (see FIG. 8) is moved to a depressed position. When the switch lifter 874
is
actuated by the control shaft lift ramp 514, the switch Sifter 874 displaces
about
0.135 of an inch (0.342 cm).
The switch lifter 874 includes a switch lifter pivot bore 894, a switch lifter
notch 896, a switch lifter spring connector 898, a switch lifter ramp 900, a
switch
lifter latch 902, and a switch lifter bar contactor 904. The switch lifter
pivot bore
894 cooperates with the housing base switch lifter pivot pin 158 to permit the
switch lifter 874 to pivot. The switch lifter notch 896 permits installation
in the
housing base 74 over retention hook 160 on a straight axis. The switch lifter
spring connector 898 provides an attachment point for the lifter spring 876 to
bias
the switch lifter 874 toward the control shaft mount 142. The switch lifter
ramp
900 is a angled at 45° to complement the control shaft lift ramp 514
that is also
45°. The switch lifter latch 902 is a reverse ramp of 60° from
the rocker lifter ramp
888 that extends about 0.006 of an inch (0.0152 cm) from the switch lifter 874
creating an overhang. When the switch lifter 874 is actuated by the control
shaft
lift ramp 514, the switch lifter 874 displaces about 0.135 of an inch (0.342
cm).
The switch lifter 874 functions to lift cam-followers blades 790 and upper
switch
blades 816 a distance sufficient to break all electrical contacts 744 within
the
blade switches thereby turning "off' the appliance 50 without the use of a
dedicated line switch.
The lifter spring 876 has lifter spring loops 906 and is optional to the
master
switch. The purpose of the lifter spring 876 is to provide an additional
biasing
force of about 0.625 Ibs (0.284 Kg) for biasing the rocker lifter 872 and
switch lifter
874 toward the control shaft lift bearing 518. The additional biasing force
supplied
by the spring creates a more positive feel for the operator when the operator
extends the control shaft 438 (see FIG. 8) to place the cam-operated timer 52
in
operation.
The rocker 878 includes a rocker pivot 908 and rocker tabs 910. The
rocker cradle 166 is located in the rocker mount 164. The rocker cradle 166
acts
as a bearing surface for the rocker 878 as the rocker 878 pivots during
operation
of the master circuit switch. The rocker 878 is symmetrical, so the rocker 878
can
be placed with either end into the rocker support 164. The rocker ends are
also
52
CA 02207543 1997-OS-28
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tapered to facilitate insertion into the rocker mount 164. The rocker arm
notch
prevents the switch lifter pivot base detail 158 from interfering with the
movement
of the rocker arm. During operation, the rocker tabs 910 move about 0.135 of
an
inch (0.343 cm).
The lift bar 880 includes a lift bar notch 912, a lift beam 914, a lift
platform
916, a switch lifter tab 918 and a switch lifter guide 920. The lift bar notch
912 is
engaged by the rocker tab 910 to displace the lift bar 880. The lift beam 914
provides a mechanical connection between the lift bar notch 912 and the lift
platform 916. The lift platform 916 has a lower lift platform 922 and an upper
lift
platform 924. The lower lift platform 922 has lower lift peaks 926, lower lift
valleys
928, and lower lift platform extensions 930. The lower lift peaks 926 contact
the
cam-follower blades 790 to lift the cam-follower blades away from the program
blades 466. The lower platform lift valleys 928 provide clearance for the
lower
blade arc barrier 784. The lower lift platform extensions 930 are used with
the
quiet cycle selector to increase lift of the cam-follower blades 790. The
upper lift
platform 924 has upper lift peaks 932 and upper lift valleys 934. The upper
lift
peaks 932 contact the upper switch blade extensions 826 to maintain an air gap
between the upper switch blades 816 and the cam-follower switch blades 790
when the master switch is actuated. The upper lift valleys 934 reduce arc
tracking
between blade switches. The switch lifter tab 918 is contacted by the switch
lifter
bar contactor 904 to move the lift bar 880 during master switch actuation. The
switch lifter guide 920 engages the housing base lift bar channel 168 to align
and
guide the lift bar 880 during actuation. The lift bar 880 is installed after
the first
side cover 76 has been attached to the housing base 74. The lift bar guides
receive, properly locate and permit a component of the quiet manual selector
to
slideably operate. The lift bar 880 is manufactured from a rigid plastic such
as a
glass and mineral filled polyester. The switch lifter tab 918 is engaged by
the
switch lifter bar contactor 904 to assist in displacing the lift bar 880.
Operation of the master switch is now discussed. It takes about 5.5 Ibs
(2.48 Kg) of force to inwardly index the control shaft 438 (see FIG. 8). It
takes
about 3.5 Ibs (1.59 Kg) of force to outwardly index the control shaft 438. The
lower lift platform 922 engages the cam-follower blades 790 to lift them about
0.020 of an inch (0.051 cm) above the program blades neutral radius 470 to
lift
the cam-follower lower electrical contacts 798 away from the lower blade
electrical
53
CA 02207543 1997-OS-28
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contacts 770. When the master switch is in the lift position, the cam-follower
riders 802 do not clear the program blade upper radius 468. Therefore when the
camstack 62 is rotated noise is created by the cam-follower riders 802
contacting
the program blade upper radius 468 and the primary drive pawl f08 and
secondary drive pawl 610 contacting the drive blade drive teeth 482. The upper
lift platform 924 engages the upper switch blades 816 to lift the upper
electrical
contacts 820 away from the cam-follower upper electrical contacts 800 to break
electrical contact. Also the camstack 62 can only be rotated in a single
direction
that is the same direction the camstack is driven. To ensure the camstack 62
is
only rotated in a single direction, the clutch 440 is configured to engage in
a single
direction.
QUIET CYCLE SELECTOR
Referring to FIG. 6, the quiet cycle selector includes the same components
as the master switch with the following substitutions and additions. The
master
switch rocker lifter 872 is substituted for a drive lifter 936 and the master
switch
lifter 874 may be substituted for a delay lifter 938 in applications having a
delay
drive 604. The previously discussed master switch components will not be
discussed except for modifications that may be made for the quiet cycle
selector.
The quiet cycle selector functions to disengage the camstack drive 64 and lift
cam-followers so that when the camstack is rotated by the control shaft,
ratcheting
noises generated by the camstack drive 64 and cam-follower slapping against
the
camstack 62 are reduced or eliminated. The quiet cycle selector also performs
the function of the master circuit switch to open all electrical circuits
thereby
turning "off' the appliance 50 without the use of a dedicated line switch.
The drive lifter 936 may also be referred to as a pawl lifter and includes a
pawl lifter pivot bore 940, a pawl lifter notch 942, a pawl lifter spring
connector
944, a pawl lifter ramp 946, a pawl lifter latch 948, a pawl lifter drive
contactor
950, a pawl lifter rocker contactor 952. The pawl lifter 936 functions to
disengage
the primary drive pawl 608 and the secondary drive pawl 610 from the camstack
primary drive blade 476 and secondary drive blade 478 during actuation of the
quiet cycle selector. The pawl lifter 936 is made from a rigid plastic with a
low
coefficient of friction such as acetal or nylon. The major difference between
the
rocker lifter 872 and the pawl lifter 936 is the pawl lifter drive contactor
950. The
54
CA 02207543 1997-OS-28
pawl lifter drive contactor 950 is wider than the primary drive pawl foot 648
because the primary drive pawl surtace has a linear movement of about 0.18 of
an
inch (0.46 cm) and at any time during this linear movement the pawl lifter 936
must be able to contact the primary drive pawl 608 and move the primary drive
pawl 608 away from the camstack ratchet. The secondary drive pawl surface is
about the same size as the secondary drive foot 662 because the secondary
drive
pawl 610 only moves about 0.006 inches (0.015 cm) during operation. Therefore,
the secondary drive pawl surface is always in position to move the secondary
drive pawl 610 when the pawl lifter 936 is displaced. The pawl lifter notch
942
permits installation in the housing base over retention hook 152 on a straight
axis.
The delay lifter 938 includes a delay lifter rocker contact 954, and a delay
rocker 956. The remaining portions of the delay lifter 938 that correspond
with
matching portions on the switch lifter 874 are configured similarly and
perform
similar functions. In addition to performing the same functions as the switch
lifter
874, the delay lifter 938 also disengages the delay camstack pawl 674 from the
camstack delay drive blade 480 during actuation of the quiet cycle selector.
The
delay rocker contact 962 imparts movement to the delay rocker 956 when the
quiet cycle selector is actuated. The delay rocker 956 includes a delay rocker
pivot bore 958, a delay rocker foot 960, a delay rocker contact 962, and a
delay
rocker pawl lifter 964.
The lift bar 880 used for the quiet cycle selector is similar to the lift bar
880
discussed above under the description of the master circuit switch with the
addition of lift extensions 930. The lift extensions 930 project about 0.070
inch
(0.178 cm) from the lower lift platform 922. The lift extensions 930 engage
the
cam-follower blade extended lift tabs 806 to lift the cam-follower blades 790
0.010
inch (0.254 cm) above the program blades top radius 468.
An objective of the quiet cycle selector is to cause the lift bar 880 to
remove
the blade switches 66 from their contact with the camstack 62 so that the
camstack 62 may be rotated in any direction without the clicking noises that
would
be present if the blade switches were engaged with the camstack 62. This
objective is accomplished by application of force to opposite ends of the lift
bar
880 in a direction toward the second side cover 78. Adequate force applied to
the
lift bar 880 in this manner causes the lift bar 880 to engage the blade
switches
and clear them from any interaction with the camstack 62.
CA 02207543 1997-OS-28
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Operation of the quiet cycle selector is now discussed. When the control
shaft 438 (see FIG. 8) is extended, i.e., pulled-out, the guiet cycle selector
is not
in operation and the camstack 62 is free to rotate on the control shaft 438 as
the
primary drive pawl 608 and secondary drive pawl 610 move the camstack. With
the control shaft 438 in the extended position, the pawl lifter actuation ramp
946
and the switch lifter actuation ramp 900 rest on the circular ramp 514 of the
control shaft 438. As the control shaft 438 is depressed, i.e., pushed-in
toward
the housing, the pawl lifter actuation ramp 946 and the switch lifter
actuation ramp
900 slide along the circular ramp (514) of the control shaft 438. This sliding
action
forces the pawl lifter 936 and the switch lifter 874 to radially move away
from the
control shaft 438 as they rotate about their respective pivots. The pawl
lifter 936
pivots in a direction away from the second side cover 78, and the switch
lifter 874
pivots toward the second side cover 78. Upon substantial depression of the
control shaft 438, when the base end of the control shaft is about to contact
the
housing base 74, the circular ramp 514 slides past the pawl lifter actuation
ramp
946 and the switch lifter actuation ramp 900, causing the control shaft 438 to
lock
in place in the depressed position. When the control shaft 438 contacts the
housing base 74, the control shaft cannot be depressed any further.
When the pawl lifter 936 pivots, the pawl lifter rocker contact surface 952
presses against the rocker 878. Force applied to the rocker 878 causes the
rocker 878 to rotate about its fulcrum. The result of rocker 878 rotation is a
force
applied by the rocker 878 opposite the force that was applied at the other end
of
the rocker 878 by the pawl lifter rocker contact surface 952. The rocker notch
of
the lift bar 880 is the recipient of the force from the rocker action. Thus,
the
movement of the pawl lifter 936 causes a force to be applied to one end of the
lift
bar 880 in a direction toward the second side cover 78. Also when the pawl
lifter
936 pivots, the pawl lifter drive contactor 950 applies pressure to the
primary drive
foot 648 to pivot both the primary drive pawl 608 and secondary drive pawl 610
out of engagement with the camstack primary drive blade 476 and secondary
drive
blade 478 respectively
When the switch lifter 874 pivots, the switch lifter bar contact surface 904
applies a force to the lift bar 880. At this point, a force is also being
applied at an
opposite end of the lift bar 880 by movement of the rocker 878. This action
causes the lift bar 880 to move toward the second side cover 78. The lift bar
880
56
CA 02207543 1997-OS-28
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s
then contacts the blade switches as it nears the second side cover 78, and
pulls
the blade switches from contact with the camstack 62. Release of the blade
switches from contact with the camstack 62 allows the camstack 62 to be
rotated
in either direction without any noise from interaction with the blade
switches. Also
in delay drive applications where the switch lifter 874 is substituted for a
delay
lifter 938, the delay lifter rocker contact 954 applies force to the delay
rocker
contact 962 that in turn applies force to the delay camstack pawl foot 700 to
pivot
the delay camstack pawl 674 out of engagement with the camstack delay drive
blade 480.
It is a feature of the quiet cycle selector that cycle selection is quieter
than
with a master switch. For instance the following data shows noise measurements
in decibels made with a cam-operated timer configured with a master switch and
a
similar cam-operated timer configured with a quiet cycle selector (QCS)
measured
at both 1 KHz and 4 KHz in decibels while rotating the control shaft at five
R.PIVI.
Configuration Noise (dB) 1 Noise (dB) 4
KHz
KHz
aster Switch 54. 5 .
57
CA 02207543 1997-OS-28
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SUBINTERVAL SWITCH
Referring to FIGs. 6 and 9, the subinterval switch includes a subinterval
lever 966, a subinterval pivot bore 968, a subinterval follower 970, a
subinterval
foot 972, a subinterval actuator 974, and a subinterval step 976. The
subinterval
switch is an optional component of the cam-operated timer 52 that functions to
operate the blade switches in response to a predetermined program carried on
the
drive cam subinterval cam 616 which is independent of camstack movement. The
subinterval switch is operated by the subinterval cam 616 to actuate the cam-
follower blade subinterval tab 810 (see FIG. 9) to operate one of the blade
switches. The subinterval switch along with the subinterval cam 616 can be
configured to operate one of the blade switches in the range of from about 1-
180
seconds. The subinterval switch is typically configured to operate one of the
blade
switches for 15-20 second intervals for machine functions such a clothes
washing
machine spray rinse. The subinterval lever 966 is stamped from a steel zinc
pre-
coated stock with the burr side of the stamping away from the housing platform
84
to facilitate installation and shaped to avoid interference with the housing
and
timer components. The subinterval switch can be configured for a single throw
to
make and break the lower blade electrical contacts 770 by actuating the cam-
follower blade subinterval tab 810 or a double throw to make and break both
the
lower electrical contacts and the upper electrical contacts 820 by actuating
the
cam-follower blade subinterval tab 810.
The subinterval pivot bore 968 cooperates with the housing base
subinterval pivot pin 110 to provide a fulcrum for operation of the
subinterval lever
966. The subinterval follower 970 cooperates with the subinterval cam 616 to
~ror..~er i- r~vta y- dr iv°c i,a~Tr ~ i ~otioi ~ tl~T a-tll tear
fllotlOn. T he subinterval foot 972
contacts the housing base platform 84 to position the subinterval follower 970
at
the level of the subinterval cam 616 and provide a bearing when the
subinterval
lever 966 pivots in response to the subinterval cam 616. The subinterval lever
966 jogs about 0.035 of an inch (0.0889 cm) near the subinterval pivot bore
968 to
assist along with the subinterval foot 972 in positioning the subinterval
follower
970 at the level of the subinterval cam 616. The subintervaB actuator 974
contacts
the cam-follower blade subinterval tab 810 to actuate a cam-follower switch
blade
790. The subinterval actuator 974 is radiused to provide a bearing surface
during
58
CA 02207543 1997-OS-28
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t
actuation. The subinterval step 976 is an option that contacts the lower blade
subinterval tab 780 which in turn through the lower blade support 782
maintains
the proper air gap between the upper blade electrical contacts 820 and the cam-
follower lower electrical contacts 798 during subinterval switch operation.
Operation of the subinterval switch is now discussed. The subinterval
follower 970 contacts the subinterval cam 616 to provide linear motion to the
subinterval lever 966. The linear motion of the subinterval follower 970 is
transferred to the subinterval actuator 974. The subinterval actuator 974
contacts
the cam-follower blade subinterval tab 810 and causes the subinterval actuator
974 to press against the cam-follower blade subinterval tab 810 to operate a
blade
switch. Operation of the subinterval switch can be masked when the camstack 62
is operating the blade switches that the subinterval switch is attempting to
operate.
59
